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2 pages, 172 KiB

Open AccessAbstract

Antitumor Cytokine DR5-B-Conjugated Polymeric Poly(N-vinylpyrrolidone) Nanoparticles with Enhanced Cytotoxicity in Human Colon Carcinoma 3D Cell Spheroids

by Anne Yagolovich, Andrey Kuskov, Pavel Kulikov, Leily Kurbanova, Anastasia Gileva and Elena Markvicheva

Mater. Proc. 2021, 7(1), 8; https://doi.org/10.3390/IOCPS2021-11281 - 1 Nov 2021

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Abstract

Self-assembled nanoparticles based on amphiphilic poly(N-vinylpyrrolidone) (Amph-PVP) were proposed earlier as a new drug delivery system. In the current work, we study the antitumor activity of Amph-PVP-based self-assembled polymeric micelles covalently conjugated with the antitumor receptor-specific TRAIL variant DR5-B (P-DR5-B). The [...] Read more.

Self-assembled nanoparticles based on amphiphilic poly(N-vinylpyrrolidone) (Amph-PVP) were proposed earlier as a new drug delivery system. In the current work, we study the antitumor activity of Amph-PVP-based self-assembled polymeric micelles covalently conjugated with the antitumor receptor-specific TRAIL variant DR5-B (P-DR5-B). The Amph-PVP polymer was synthesized by the earlier developed one-step technique (Kulikov et al., Polym. Sci. Ser. D, 2017). To stabilize Amph-PVP associates, the hydrophobic core was loaded with the model substance prothionamide. For the covalent conjugation with DR5-B, the hydrophilic ends of polymeric chains were modified with maleimide, and a DR5-B N-terminal amino acid residue valine was mutated to cysteine (DR5-B/V114C). DR5-B/V114C was conjugated to the surface of polymeric micelles by the selective covalent interaction of N-terminal cysteine residue with maleimide on Amph-PVP. The cytotoxicity of DR5-B-conjugated Amph-PVP polymeric nanoparticles was investigated in 3D multicellular tumor spheroids (MCTS) of human colon carcinoma HCT116 and HT29 cells, generated by the RGD-induced self-assembly technique (Akasov et al., Int. J. Pharm., 2016). In DR5-B-sensitive HCT116 MCTS, the P-DR5-B activity slightly increased compared to that of DR5-B. However, in DR5-B-resistant HT29 MCTS, P-DR5-B significantly surpassed DR5-B in the antitumor activity. Thus, the conjugation of DR5-B with the Amph-PVP nanoparticles enhanced its tumor-cell killing capacity. In the current study, we obtain a new nano-scaled delivery system based on Amph-PVP self-aggregates coated with covalently conjugated antitumor DR5-specific cytokine DR5-B. P-DR5-B overcomes DR5-B-resistance of the human colon carcinoma MCTS in vitro. This makes Amph-PVP polymeric nanoparticles a prospective and versatile nano-scaled delivery system for the targeted proteins. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

1 pages, 165 KiB

Open AccessAbstract

Vitrimerization of Poly(butylene succinate) By Reactive Melt Mixing Using Zn(II) Epoxy-Vitrimer Chemistry

by Christos Panagiotopoulos, Dimitrios Korres and Stamatina Vouyiouka

Mater. Proc. 2021, 7(1), 10; https://doi.org/10.3390/IOCPS2021-11588 - 5 Nov 2021

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Abstract

Vitrimers constitute a new class of covalent adaptable networks (CANs), in which thermally stimulated associative exchange reactions allow the topological rearrangement of the dynamic network while keeping the number of bonds and the crosslink density constant. The current study proposed a solvent-free method [...] Read more.

Vitrimers constitute a new class of covalent adaptable networks (CANs), in which thermally stimulated associative exchange reactions allow the topological rearrangement of the dynamic network while keeping the number of bonds and the crosslink density constant. The current study proposed a solvent-free method to synthesize vitrimers by reactive melt mixing using a commercial biobased/biodegradable polyester, poly(butylene succinate), PBS. More specifically, a two-step process was followed; the first step involved reactive mixing of PBS with the crosslinker (diglycidyl ether of bisphenol A, DGEBA) and the transesterification catalyst (Zinc(II) acetylacetonate hydrate, Zn(acac)2) in a twin-screw mini-compounder, in order to incorporate the epoxy groups in the polymer backbone. The second step (vitrimerization) comprised a crosslinking process of the homogenous mixtures in a vacuum oven at 170 °C, resulting in the formation of a dynamic crosslinked network with epoxy moieties serving as the crosslinkers. By tuning the crosslinker content (0–10% mol with respect to PBS repeating unit) and the Zinc(II) catalyst to crosslinker ratio (0 to 1), tailor-made vitrimers were prepared with high insolubility and improved melt strength. Moreover, PBS vitrimers could still be reprocessed by compression molding after the crosslinking, which enables the recycling process. This work was made possible by the “Basic Research Programme, NTUA, PEVE 2020 NTUA” [PEVE0050] of the National Technical University of Athens and is gratefully acknowledged. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

1 pages, 162 KiB

Open AccessAbstract

Evaluation of the Parameters of Poly(Butylene succinate) Enzymatic Polymerization

by Christina I. Gkountela, Dimitrios N. Markoulakis, Dimitrios M. Korres and Stamatina N. Vouyiouka

Mater. Proc. 2021, 7(1), 11; https://doi.org/10.3390/IOCPS2021-11274 - 1 Nov 2021

Viewed by 886

Abstract

Poly(butylene succinate) (PBS) is a bio-based and biodegradable polyester that can be used in numerous applications, ranging from clothing to food packaging and from the car industry to the biomedical sector (e.g., drug release systems). The conventional polymerization method of PBS requires the [...] Read more.

Poly(butylene succinate) (PBS) is a bio-based and biodegradable polyester that can be used in numerous applications, ranging from clothing to food packaging and from the car industry to the biomedical sector (e.g., drug release systems). The conventional polymerization method of PBS requires the presence of metal-based transesterification catalysts (e.g., titanium-based catalysts) and high reaction temperatures (T > 150 °C). However, under these conditions side reactions may occur along with undesirable yellowing. Green polymerization routes such as biocatalysis are being developed. However, there is a very limited literature on the enzymatic synthesis of PBS. Additionally, in most of the works where high-molecular-weight PBS is produced from the typical monomers (BDO and DES), several drawbacks, e.g., the use of various solvents for polymer isolation and the requirement of high vacuum for by-products removal may impede the process being scaled up. On that basis, an eco-friendly, solvent-free, enzyme-based process for the production of PBS was applied. It was conducted in two steps with the use of Novozym 435: the first at 40 °C, under atmospheric pressure for 24 h, and the second at 90 °C, 20 mbar for 2 h. This work focused on the optimization of the second step’s conditions, by varying reaction temperature (80–95 °C), pressure (20 mbar, 200 mbar) and reaction time (2 h, 6 h). Based on the optimization results, the process was scaled up (ca. 10 g of product). A PBS grade free of thermal degradation and metal catalyst residues, of weight-average molecular weight 4700 g/mol and melting point 103 °C, was obtained. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

1 pages, 154 KiB

Open AccessAbstract

A Novel 3D Microporous Structure Hydrogel with Stable Mechanical Properties and High Elasticity and Its Application in Sensing

by Chunyin Lu, Jianhui Qiu, Eiichi Sakai and Guohong Zhang

Mater. Proc. 2021, 7(1), 15; https://doi.org/10.3390/IOCPS2021-11212 - 20 Oct 2021

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Abstract

Hydrogels have recently been increasingly studied due to their similarity to natural soft tissues. However, the stable mechanical properties and elasticity required for hydrogels used in sensing and wearable devices remain challenging. Herein, a novel 3D microporous structure hydrogel with favorable stable mechanical [...] Read more.

Hydrogels have recently been increasingly studied due to their similarity to natural soft tissues. However, the stable mechanical properties and elasticity required for hydrogels used in sensing and wearable devices remain challenging. Herein, a novel 3D microporous structure hydrogel with favorable stable mechanical properties and elasticity is developed via a simple and economical method. The good resilience (94.5%) and lower residual strain (11.5%) are realized based on the results of 20 successive cycles at a strain of 300%. The elasticity of the hydrogel is achieved by varying the effective network chain density. The prepared hydrogel has stable mechanical properties and a high elasticity, resulting in remarkable performance when used in sensors. The hydrogel-based sensors can accurately and consistently record human activities when used as wearable sensors. This work provides a new way to simply and effectively prepare hydrogels, which has great potential to be widely applicated in sensing and flexible devices, such as health-recording sensors, wearable devices, and artificial intelligence. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

2 pages, 173 KiB

Open AccessAbstract

Biopolymer-Based Hydrogels for 3D Bioprinting

by Ahmed Fatimi, Oseweuba Valentine Okoro and Amin Shavandi

Mater. Proc. 2021, 7(1), 19; https://doi.org/10.3390/IOCPS2021-11284 - 1 Nov 2021

Cited by 2 | Viewed by 1031

Abstract

Three-dimensional (3D) bioprinting is an emerging technology that could be used in the generation of 3D cellular structures for tissue engineering applications. The interest in this technology is due to its capacity to enable the fabrication of precise 3D constructs composed of biomaterials [...] Read more.

Three-dimensional (3D) bioprinting is an emerging technology that could be used in the generation of 3D cellular structures for tissue engineering applications. The interest in this technology is due to its capacity to enable the fabrication of precise 3D constructs composed of biomaterials laden with living cells, biomolecules, and nutrients. The process involving the deposition of cell-laden biomaterials or bioinks on a substrate is referred to as bioprinting. This bioprinting process can be used in the fabrication of living tissues and functional organs suitable for transplantation into the human body. Notably, the viability of utilising a bioink for bioprinting is dependent on its functionality, mechanical properties, printability, and biocompatibility. The bioink must also be able to provide cells with a stable environment for attachment, proliferation, and differentiation. To promote the sufficiency of bioinks in 3D bioprinting, several researchers have investigated pathways to enhance ink properties to meet bioprinting requirements, with several synthetic and natural hydrogels developed. These hydrogels are matrices made up of a network of hydrophilic polymers that absorb biological fluids. They can be created from a large number of water-soluble biopolymers including proteins and polysaccharides. The 3D structure of these hydrogels is due to the presence of structural crosslinks that are maintained the environmental fluid. The elasticity of these structures and the presence of a large amount of water enable the hydrogel to adequately mimic biological tissues. Recognising the importance of hydrogels in 3D bioprinting and its potential wide range of tissue engineering applications, the current study therefore investigated major physicochemical parameters that may affect the printability and biocompatibility of biopolymer-based hydrogels. Approaches employed in maintaining structural integrity of the hydrogel, via the application of crosslinking methods, were comprehensively discussed with explorations of the status of the formulation and the use of biopolymer-based hydrogels for 3D bioprinting is also presented. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

1 pages, 372 KiB

Open AccessAbstract

A Novel Treatment Tool for PLA-Based Encapsulation Systems

by Konstantina Chronaki, Angeliki Mytara, Constantine D. Papaspyrides, Konstantinos Beltsios and Stamatina Vouyiouka

Mater. Proc. 2021, 7(1), 21; https://doi.org/10.3390/IOCPS2021-11268 - 1 Nov 2021

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Abstract

Active-compound encapsulation in polymeric carriers is a widely used technology as it protects and improves the physical characteristics of the active compound and controls its delivery. The effectiveness of polymeric microcapsules (MCs) depends on the barrier properties of the polymeric shell; for a [...] Read more.

Active-compound encapsulation in polymeric carriers is a widely used technology as it protects and improves the physical characteristics of the active compound and controls its delivery. The effectiveness of polymeric microcapsules (MCs) depends on the barrier properties of the polymeric shell; for a given polymer, the latter properties are affected by its molecular weight (MW) and crystallinity (x_c). The aim of this study was to modify the MW and x_c of the MCs shell via solid state polymerization (SSP). SSP may take place in the amorphous regions of the polymer upon heating at temperatures higher than the glass transition point (T_g) but lower than the onset of melting (T_m). Poly(lactic acid) (PLA) was chosen as the polymeric carrier and coumarin 6 as the encapsulated compound. PLA is a biobased and biodegradable polymer that is widely used in drug delivery systems, and coumarin 6 is a fluorescent hydrophobic drug that can be used as model compound. The effectiveness of SSP as a post-encapsulation tool was proven for blank PLA MCs of two molecular weights (MW = 50,000 g mol⁻¹ and 20,000 g mol⁻¹). SSP led to a 40–50% enhancement of the weight-average molecular weight of the polymeric shell and to an enhancement, from 40% to up to 70%, of the mass fraction crystallinity in the case of the low-MW MCs. In an attempt to transfer the gained knowledge to the encapsulation systems, coumarin-6-loaded MCs were prepared. The average size of the MCs was measured at 502 nm with a polydispersity index of 1.6 while the encapsulation efficiency was found to be 15% for a drug loading of 10%. UV–Vis measurements showed that the compound was fully released after 10 days. Coumarin 6 was found to be thermally stable at temperatures used for SSP, while the study of SSP application in the case of loaded MCs is in progress. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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5 pages, 1234 KiB

Open AccessProceeding Paper

Synthesis and Study of Microcapsules with Beeswax Core and Phenol-Formaldehyde Shell Using the Taguchi Method

by Tejashree Amberkar and Prakash Mahanwar

Mater. Proc. 2021, 7(1), 1; https://doi.org/10.3390/IOCPS2021-11207 - 20 Oct 2021

Cited by 1 | Viewed by 1522

Abstract

Phenol-formaldehyde shelled phase change material microcapsules (MPCMs) were fabricated and their processing parameters were analyzed with the Taguchi method. Core to shell ratio, surfactant concentration and speed of mixing are the parameters that were optimized in five levels. The optimized values for the [...] Read more.

Phenol-formaldehyde shelled phase change material microcapsules (MPCMs) were fabricated and their processing parameters were analyzed with the Taguchi method. Core to shell ratio, surfactant concentration and speed of mixing are the parameters that were optimized in five levels. The optimized values for the surfactant concentration, core to shell ratio and agitation speed were 3%, 1:1 and 800 rpm, respectively. The obtained microcapsules were spherical in shape. The melting enthalpy of the MPCMs synthesized with optimized processing parameters was 148.93 J/g in 35–62 °C. The obtained temperature range of phase transition temperature can be used for storing different food articles such as chocolate and hot served foods. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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6 pages, 224 KiB

Open AccessProceeding Paper

Bora Rice: Natural Polymer for Drug Delivery

by Kalyani Pathak, Ratna Jyoti Das, Riya Saikia, Aparoop Das and Mohammad Zaki Ahmad

Mater. Proc. 2021, 7(1), 2; https://doi.org/10.3390/IOCPS2021-11290 - 1 Nov 2021

Cited by 1 | Viewed by 1631

Abstract

Natural polymers play a vital part in the formulation of pharmaceutical dosage forms due to their use as excipients. Synthetic polymers have been introduced into drug delivery recently; the usage of natural polymers in drug delivery research continues to rise. It is not [...] Read more.

Natural polymers play a vital part in the formulation of pharmaceutical dosage forms due to their use as excipients. Synthetic polymers have been introduced into drug delivery recently; the usage of natural polymers in drug delivery research continues to rise. It is not surprising that applications other than its caloric value have been found for starch. Various natural sources of the polymer have been investigated for delivery systems; among them, Assam Bora rice starch seems to be a promising candidate due to its interesting properties such as being non-toxic, biocompatible, biodegradable, mucoadhesive, and non-immunogenic. Assam Bora rice, locally known as Bora Chaul, was first introduced in Assam, India, from Thailand or Myanmar by Thai-Ahom, now widely cultivated throughout the Assam. The starch obtained from Assam Bora rice is characterized by its high amylopectin content (i.e., >95%) with a branched, waxy polymer which shows physical stability and resistance towards enzymatic action. Assam Bora rice starch hydrates and swells in cold water, forming viscous colloidal dispersion or sols responsible for its bioadhesive nature. Moreover, it is degraded by colonic bacteria but remains undigested in the upper GIT. Due to the excellent adhesion and gelling capability, it is often selected as a mucoadhesive matrix in a controlled release drug delivery system. Carboxymethyl Assam Bora rice starch has also been applied for SPIONs stabilization and, further, it can effectively bind and load cationic anti-cancer drug molecule, Doxorubicin hydrochloride (DOX), via electrostatic interaction. This article provides a critical assessment of Assam Bora rice literature and shows how the rice can be used in many ways, from food additives to drug delivery systems. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

7 pages, 697 KiB

Open AccessProceeding Paper

Hydrogel-Based Bioinks for Three-Dimensional Bioprinting: Patent Analysis

by Ahmed Fatimi

Mater. Proc. 2021, 7(1), 3; https://doi.org/10.3390/IOCPS2021-11239 - 30 Oct 2021

Cited by 12 | Viewed by 2677

Abstract

There are a variety of hydrogel-based bioinks commonly used in three-dimensional bioprinting. In this study, in the form of patent analysis, the state of the art has been reviewed by introducing what has been patented in relation to hydrogel-based bioinks. Furthermore, a detailed [...] Read more.

There are a variety of hydrogel-based bioinks commonly used in three-dimensional bioprinting. In this study, in the form of patent analysis, the state of the art has been reviewed by introducing what has been patented in relation to hydrogel-based bioinks. Furthermore, a detailed analysis of the patentability of the used hydrogels, their preparation methods and their formulations, as well as the 3D bioprinting process using hydrogels, have been provided by determining publication years, jurisdictions, inventors, applicants, owners, and classifications. The classification of patents reveals that most inventions intended for hydrogels used as materials for prostheses or for coating prostheses are characterized by their function or properties Knowledge clusters and expert driving factors show that biomaterials, tissue engineering, and biofabrication research is concentrated in the most patents. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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7 pages, 1205 KiB

Open AccessProceeding Paper

RAFT-Mediated Radiation Grafting on Natural Fibers in Aqueous Emulsion

by Bin Jeremiah D. Barba, David P. Peñaloza, Jr., Noriaki Seko and Jordan F. Madrid

Mater. Proc. 2021, 7(1), 4; https://doi.org/10.3390/IOCPS2021-11243 - 30 Oct 2021

Cited by 1 | Viewed by 1696

Abstract

Using aqueous emulsion as the medium in radiation-induced graft polymerization (RIGP) offers an environment-friendly shift from organic solvents while increasing polymerization efficiency through known water radiolysis-based graft initiation. In the present paper, we further extend the applicability of RIGP in emulsion under the [...] Read more.

Using aqueous emulsion as the medium in radiation-induced graft polymerization (RIGP) offers an environment-friendly shift from organic solvents while increasing polymerization efficiency through known water radiolysis-based graft initiation. In the present paper, we further extend the applicability of RIGP in emulsion under the influence of reversible addition fragmentation chain transfer (RAFT) mechanisms. Emulsions prepared with Tween 20 showed good colloidal stability for several hours. Subjecting it to simultaneous irradiation with abaca fibers resulted in successful grafting, supported by gravimetric, IR, SEM, and TG analysis. A correlation was drawn between smaller monomer micelles and the enhancement of grafting driven by diffusion and surface area coverage. RAFT mechanisms were also conserved based on molecular weight evolution. RAFT-mediated RIGP in aqueous emulsion shows good potential as a versatile and green surface modification technique for natural fibers for various functional applications. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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7 pages, 1355 KiB

Open AccessProceeding Paper

Nanografting of Polymer Brushes on Gold Substrate by RAFT-RIGP

by Bin Jeremiah D. Barba, Patricia Nyn L. Heruela, Patrick Jay E. Cabalar, John Andrew A. Luna, Allan Christopher C. Yago and Jordan F. Madrid

Mater. Proc. 2021, 7(1), 5; https://doi.org/10.3390/IOCPS2021-11587 - 5 Nov 2021

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Abstract

Optical sensors based on surface plasmon resonance (SPR) have made great strides in the detection of various chemical and biological analytes. A surface plasmon is a bound, non-radiative evanescent wave generated as resonant electrons on a metal–dielectric surface to absorb energy from an [...] Read more.

Optical sensors based on surface plasmon resonance (SPR) have made great strides in the detection of various chemical and biological analytes. A surface plasmon is a bound, non-radiative evanescent wave generated as resonant electrons on a metal–dielectric surface to absorb energy from an incident light. As analytes bind to a functionalized metal substrate, the refractometric response generated can be used for quantitation with great selectivity, sensitivity, and capacity for label-free real-time analysis. Polymer nanobrushes are ideal recognition elements because of their greater surface area and their wide range of functional versatility. Here, we introduce a simple “grafting-from” method to covalently attach nanometer-thick polymer chains on a gold surface. Nanografting on gold-coated BK-7 glass was performed in two steps: (1) self-assembly of organosulfur compounds; and (2) RAFT-mediated radiation-induced graft polymerization (RAFT-RIGP) of polyglycidyl methacrylate (PGMA). Surface modification was monitored and verified using FTIR and SPR. Layer-by-layer thickness calculated based on Winspall 3.02 simulation fitted with experimental SPR curves showed successful self-assembly of 1-dodecanethiol (DDT) monolayer with thickness measuring 1.4 nm. These alkane chains of DDT served as the graft initiation sites for RAFT-RIGP. Nanografting was controlled by adjusting the absorbed dose in the presence of chain transfer agent, 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid. The molecular weight of grafted polymers measuring 2.8 and 4.3 kDa corresponded to a thickness increase of 3.6 and 7.9 nm, respectively. These stable nanografted gold substrates may be further functionalized for sensing applications. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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8 pages, 2773 KiB

Open AccessProceeding Paper

The Influence of Adding a Functionalized Fluoroalkyl Silanes (PFDTES) into a Novel Silica-Based Hybrid Coating on Corrosion Protection Performance on an Aluminium 2024-t3 Alloy

by Magdi H. Mussa, Yaqub Rahaq, Sarra Takita, Farah D. Zahoor, Nicholas Farmilo and Oliver Lewis

Mater. Proc. 2021, 7(1), 6; https://doi.org/10.3390/IOCPS2021-11240 - 30 Oct 2021

Cited by 2 | Viewed by 1774

Abstract

Silica-based coatings prepared using sol-gel polymerizing technology have been shown to exhibit excellent chemical stability combined with reducing the corrosion of metal substrates, showing promising use in aerospace and marine applications to protect light alloys. Moreover, this technology is an eco-friendly technique route [...] Read more.

Silica-based coatings prepared using sol-gel polymerizing technology have been shown to exhibit excellent chemical stability combined with reducing the corrosion of metal substrates, showing promising use in aerospace and marine applications to protect light alloys. Moreover, this technology is an eco-friendly technique route for producing surface coatings, showing high potential for replacing toxic pre-treatment coatings of traditional conversation chromate coatings. This study aims to investigate the enhancement in corrosion protection of a hybrid-organic-inorganic silica-based coating cured at 80 °C by increasing the hydrophobicity to work on the aluminium 2024-T3 alloy. This approach involving a novel silica-based hybrid coating was prepared by introducing 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) into the base hybrid formula created from tetraethylorthosilicatesilane (TEOS) and triethoxymethylsilane (MTMS) precursors; this formula was enhanced by introducing a Polydimethylsiloxane polymer (PDMS). The corrosion protection properties of these coatings were examined by being immersed in 3.5% NaCl with electrochemical impedance testing (EIS) and Potentiodynamic polarization scanning (PDPS). The chemical elements confirmation was performed using infrared spectroscopy (ATR-FTIR); all this was supported by analysing the surface morphology before and after the immersion by using scanning electron microscopy (SEM). The results of the electrochemical impedance testing analyses reveal the new open finite-length diffusion circuit element due to electrolyte media diffusion prevented by fluorinated groups. Additionally, it shows increases in corrosion protection arising from the increasing hydrophobicity of the fluorinated coating compared to other formulas cured under similar conditions and bare substrate. Additionally, the modified sol-gel exhibited improved resistance to cracking, while the increased hydrophobicity may also promote self-cleaning. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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6 pages, 1221 KiB

Open AccessProceeding Paper

Hyaluronic Acid Hydrogel Particles Obtained Using Liposomes as Templates

by Irene Abelenda Núñez, Ramón G. Rubio, Francisco Ortega and Eduardo Guzmán

Mater. Proc. 2021, 7(1), 7; https://doi.org/10.3390/IOCPS2021-11222 - 25 Oct 2021

Viewed by 1097

Abstract

Hydrogels (HG) are 3D networks of hydrophilic macromolecules linked by different “cross-linking points”, which have as a main advantage their capacity for the adsorption of large amounts of water without any apparent dissolution. This allows hydrogels to undergo reversible swelling–shrinking processes upon the [...] Read more.

Hydrogels (HG) are 3D networks of hydrophilic macromolecules linked by different “cross-linking points”, which have as a main advantage their capacity for the adsorption of large amounts of water without any apparent dissolution. This allows hydrogels to undergo reversible swelling–shrinking processes upon the modification of the environmental conditions (pH, ionic strength or temperature). This stimuli-responsiveness and their ability for entrapping in their interior different types of molecules makes hydrogels suitable platforms for drug delivery applications. Furthermore, HGs exhibit certain similarities to the extracellular tissue matrix and can be used as a support for cell proliferation and migration. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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8 pages, 5045 KiB

Open AccessProceeding Paper

Light-Driven Integration of Graphitic Carbon Nitride into Polymer Materials

by Cansu Esen and Baris Kumru

Mater. Proc. 2021, 7(1), 9; https://doi.org/10.3390/IOCPS2021-11590 - 5 Nov 2021

Viewed by 1284

Abstract

As a metal-free polymeric semiconductor with an absorption in the visible range, carbon nitride has numerous advantages for photo-based applications spanning hydrogen evolution, CO₂ reduction, ion transport, organic synthesis and organic dye degradation. The combination of g-C₃N₄ and polymer [...] Read more.

As a metal-free polymeric semiconductor with an absorption in the visible range, carbon nitride has numerous advantages for photo-based applications spanning hydrogen evolution, CO₂ reduction, ion transport, organic synthesis and organic dye degradation. The combination of g-C₃N₄ and polymer networks grants mutual benefit for both platforms, as networks are upgraded with photoactivity or formed by photoinitiation, and g-C₃N₄ is integrated into novel applications. In the present contribution, some of the recently published projects regarding g-C₃N₄ and polymeric materials will be highlighted. In the first study, organodispersible g-C₃N₄ were incorporated into a highly commercialized porous resin called poly(styrene-co-divinylbenzene) through suspension photopolymerization, and performances of resulting beads were investigated as recyclable photocatalysts. In the other study, g-C₃N₄ nanosheets were embedded in porous hydrogel networks, and so-formed hydrogels with photoactivity were transformed either into a ‘hydrophobic hydrogel’ or pore-patched materials via secondary network introduction, where both processes were accomplished via visible light. Since g-C₃N₄ is an organic semiconductor exhibiting sufficient charge separation under visible light illumination, a novel method for the oxidative photopolymerization of EDOT was successfully accomplished. As a result of the absence of dissolved anions during polymerization, so-formed neutral PEDOT is a highly viscous liquid that can be processed and post-doped easily, and grants facile coating processes. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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7 pages, 917 KiB

Open AccessProceeding Paper

Optimization of Foamed Polyurethane/Ground Tire Rubber Composites Manufacturing

by Adam Olszewski, Paulina Kosmela, Łukasz Zedler, Krzysztof Formela and Aleksander Hejna

Mater. Proc. 2021, 7(1), 12; https://doi.org/10.3390/IOCPS2021-11244 - 30 Oct 2021

Cited by 3 | Viewed by 1327

Abstract

The development of the automotive sector and the increasing number of vehicles all over the world poses multiple threats to the environment. One of them, probably not so emphasized as others, is the enormous amount of post-consumer car tires. Due to the potential [...] Read more.

The development of the automotive sector and the increasing number of vehicles all over the world poses multiple threats to the environment. One of them, probably not so emphasized as others, is the enormous amount of post-consumer car tires. Due to the potential fire threat, waste tires are considered as dangerous waste, which should not be landfilled, so it is essential to develop efficient methods of their utilization. One of the possibilities is their shredding and application of resulting ground tire rubber (GTR) as filler for polymer composites, which could take advantage of the excellent mechanical performance of car tires. Nevertheless, due to the poor compatibility with majority of polymer matrices, prior to the application, surface of GTR particles should be modified and activated. In the presented work, the introduction of thermo-mechanically modified GTR into flexible foamed polyurethane matrix was analyzed. Isocyanates can be found among the compounds applied during manufacturing of polyurethane foams, which are able to react and generate covalent bonds with the functional groups present on the surface of modified GTR. Such an effect can noticeably enhance the interfacial interactions and boost up the mechanical performance. Nevertheless, it requires the adjustment of formulations used during manufacturing of foams. Therefore, for better understanding of the process foams with varying isocyanate index (from 0.8 to 1.2) were prepared with and without taking into account the possible interactions with functional groups of GTR. For comparison, an unfilled matrix and composite containing deactivated GTR were also prepared. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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8 pages, 1956 KiB

Open AccessProceeding Paper

Gel Properties of Carboxymethyl Hyaluronic Acid/Polyacrylic Acid Hydrogels Prepared by Electron Beam Irradiation

by Alvin Kier R. Gallardo, Lorna S. Relleve and Alyan P. Silos

Mater. Proc. 2021, 7(1), 13; https://doi.org/10.3390/IOCPS2021-11220 - 25 Oct 2021

Cited by 2 | Viewed by 1320

Abstract

Semi-synthetic hydrogels made of carboxymethyl hyaluronic acid (CMHA) and polyacrylic acid (PAA) were synthesized using electron beam irradiation. CMHA, with a degree of substitution of 0.87 and a molecular weight of 149 kDa, was mixed with linear PAA and slightly crosslinked PAA (Carbopol). [...] Read more.

Semi-synthetic hydrogels made of carboxymethyl hyaluronic acid (CMHA) and polyacrylic acid (PAA) were synthesized using electron beam irradiation. CMHA, with a degree of substitution of 0.87 and a molecular weight of 149 kDa, was mixed with linear PAA and slightly crosslinked PAA (Carbopol). The equal weight ratio of the CMHA-Carbopol blends (10% CMHA, 10% Carbopol) was successfully crosslinked, even at a low irradiation dose of 20 kGy, producing a hydrogel with 60% gel fraction and 430 g/g degrees of swelling. The gel properties of this formulation showed good stability when exposed in PBS (pH 7.4) at 37 °C. Furthermore, the FT-IR spectra of the 10% CMHA, 10% Carbopol blends showed an increase in peak intensity at 1405 cm⁻¹ due to the neutralization reaction between the COOH and COO^- groups of PAA and CMHA polymers. The interaction effects between the concentration of CMHA and PAA and varying irradiation doses in the gel properties in CMHA-PAA hydrogels will be explored in a future study. Radiation crosslinking of biocompatible CMHA to other synthetic polymers, such as PAA, provides a cleaner method of producing biomaterials with tunable properties that are ideal for pharmaceutical, medical, and cosmetic applications. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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6 pages, 877 KiB

Open AccessProceeding Paper

Review on Thermal Energy Storing Phase Change Material-Polymer Composites in Packaging Applications

by Tejashree Amberkar and Prakash Mahanwar

Mater. Proc. 2021, 7(1), 14; https://doi.org/10.3390/IOCPS2021-11218 - 25 Oct 2021

Cited by 3 | Viewed by 2129

Abstract

Thermally sensitive food and pharma packages are maintained at desired temperatures using refrigeration systems. These systems are powered by non-conventional energy resources. They provide uneven cooling in large containers. Interruption in their functioning during supply chain activities increases their energy requirements. Studies revealed [...] Read more.

Thermally sensitive food and pharma packages are maintained at desired temperatures using refrigeration systems. These systems are powered by non-conventional energy resources. They provide uneven cooling in large containers. Interruption in their functioning during supply chain activities increases their energy requirements. Studies revealed that using phase change material (PCM)-polymer composites in refrigeration systems and packaging containers curtailed energy utilization for maintaining a consistent temperature. These composites maintain a temperature around its phase change temperature by absorbing or releasing latent heat. This review discusses different designs of PCM-polymer composites that maintain the temperature of big shipments and small containers. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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7 pages, 1497 KiB

Open AccessProceeding Paper

Assessment of Recycled PLA-Based Filament for 3D Printing

by Antonella Patti, Stefano Acierno, Gianluca Cicala, Mauro Zarrelli and Domenico Acierno

Mater. Proc. 2021, 7(1), 16; https://doi.org/10.3390/IOCPS2021-11209 - 20 Oct 2021

Cited by 8 | Viewed by 3321

Abstract

This study investigated the possibility of replacing virgin matrices with recycled polymers in additive manufacturing (AM). In this regard, two commercial filaments, made from polylactide acid (PLA)—the second (here referred to as recycled) obtained from the recovery of waste production of the first [...] Read more.

This study investigated the possibility of replacing virgin matrices with recycled polymers in additive manufacturing (AM). In this regard, two commercial filaments, made from polylactide acid (PLA)—the second (here referred to as recycled) obtained from the recovery of waste production of the first one (here referred to as virgin)—were initially characterized using infrared (IR) spectroscopy, thermogravimetric analysis (TGA) and dynamic rheology. Then, filaments were extruded in a 3D printer and characterized by dynamic mechanical analysis (DMA). Despite a small reduction in the intensity of correspondence of typical absorption bands of the PLA polymer, in the case of the recycled material compared to the virgin one (as attested by IR spectra), the thermal-mechanical results allow us to attest the very similar characteristics of recycled and neat filaments. The onset of thermal degradation was found at around 315 °C in both systems. Both materials exhibited the same frequency- and time-dependent trends of the complex viscosity, with a reduction of approximately 30% after 10 min of testing. When samples were dried at 80 °C under vacuum for 10 h, the stabilization of rheological features against time was improved. There was no significant difference in the storage modulus (E’) and dissipation factor (tan delta) of 3D printed parts made with different types of PLA-based filaments. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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8 pages, 4081 KiB

Open AccessProceeding Paper

Study and Characterization of Phase Change Material-Recycled Paperboard Composite for Thermoregulated Packaging Applications

by Tejashree Amberkar and Prakash Mahanwar

Mater. Proc. 2021, 7(1), 17; https://doi.org/10.3390/IOCPS2021-11208 - 20 Oct 2021

Cited by 2 | Viewed by 1445

Abstract

Beeswax is a bioderived phase change material (PCM), with a phase change temperature of around 60 °C, which is suitable for thermoregulating hot served food packages. Beeswax should be shape stabilized for thermoregulation purposes. This paper has used recycled paperboard as the matrix [...] Read more.

Beeswax is a bioderived phase change material (PCM), with a phase change temperature of around 60 °C, which is suitable for thermoregulating hot served food packages. Beeswax should be shape stabilized for thermoregulation purposes. This paper has used recycled paperboard as the matrix for shape stabilizing beeswax. Beeswax showed melting enthalpy of 216.09 J/g and melting enthalpy of composite with beeswax content 45% was 102.51 J/g. Thermal conductivity of beeswax and composite with 45% beeswax was calculated with the T-history method as 0.285 and 0.157, respectively. To address concerns, such as toxicity, environment-friendly nature and recycling, beeswax-recycled paperboard composite should be considered as a promising candidate. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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8 pages, 421 KiB

Open AccessProceeding Paper

Current Alternatives for In-Can Preservation of Aqueous Paints: A Review

by Pieter Samyn, Joey Bosmans and Patrick Cosemans

Mater. Proc. 2021, 7(1), 18; https://doi.org/10.3390/IOCPS2021-11245 - 30 Oct 2021

Cited by 1 | Viewed by 3619

Abstract

With the transition towards more sustainable paint formulations that are waterborne, the susceptibility to microbial contamination has to be better controlled to increase shelf life and functional lifetime. However, recent restrictions in European regulations on the use of biocides have put limitations on [...] Read more.

With the transition towards more sustainable paint formulations that are waterborne, the susceptibility to microbial contamination has to be better controlled to increase shelf life and functional lifetime. However, recent restrictions in European regulations on the use of biocides have put limitations on the concentrations for traditional systems providing either in-can or dry-film preservation. The commercial technologies for in-can preservation that are currently available are based on isothiazolines, such as 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT) and 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT). At present, however, only a limited number of alternatives can be used and are reviewed in this presentation. Examples of non-sensitizing biocidal components for coatings include quaternary/cationic nitrogen amines, silver ions and zinc complexes. However, the use of the latter is not without risk to human health. Therefore, it is believed that disruptive methods will need to be implemented in parallel with more innovative bio-inspired solutions. In particular, the antimicrobial polymers, amino-acid-based systems and peptides have similar functions in nature and can offer antimicrobial activities. Additionally, cross-border solutions currently applied in food or cosmetics industries should be considered as examples that need to be further adapted for paint formulations. However, incorporation in paint formulations remains a challenge in view of the stabilization and rheology control needed for paint. This work’s overview aims to provide different strategies and best evidence for future trends. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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5 pages, 1098 KiB

Open AccessProceeding Paper

Preparation and Characterisation of PBAT-Based Biocomposite Materials Reinforced by Protein Complex Microparticles

by Elena Togliatti, Cosimo C. Laporta, Maria Grimaldi, Olimpia Pitirollo, Antonella Cavazza, Diego Pugliese, Daniel Milanese and Corrado Sciancalepore

Mater. Proc. 2021, 7(1), 20; https://doi.org/10.3390/IOCPS2021-12019 - 2 Dec 2021

Cited by 2 | Viewed by 1449

Abstract

In this work, new biodegradable composite materials based on poly (butylene adipate terephthalate) (PBAT) reinforced with zein–TiO₂ complex microparticles were prepared and characterised by electron microscopy and tensile and dynamic-mechanical tests. The composite pellets were prepared by solvent casting with different filler [...] Read more.

In this work, new biodegradable composite materials based on poly (butylene adipate terephthalate) (PBAT) reinforced with zein–TiO₂ complex microparticles were prepared and characterised by electron microscopy and tensile and dynamic-mechanical tests. The composite pellets were prepared by solvent casting with different filler contents, namely 0, 5.3, 11.1 and 25 part per hundred resin (phr), to modify and modulate the properties of the final materials. Scanning electron microscopy (SEM) images showed homogeneous dispersion of the filler, without microparticles aggregation or phase separation between filler and matrix, suggesting a good interphase adhesion. According to tensile tests, Young’s modulus showed an improvement in the rigidity and the yield stress presented an increasing trend, with opposite behaviour compared to other composites. Dynamic-mechanical analysis (DMA) results exhibited increasing storage modulus values, confirming a greater rigidity with a higher filler percentage. The glass transition temperature showed a slightly increasing trend, meaning the presence of an interaction between the two phases of the composite materials. Overall, the produced PBAT composites showed similar properties to low-density polyethylene (LDPE), proving to be promising and more sustainable alternatives to traditional polymers commonly adopted in agri-food fields. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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5 pages, 1035 KiB

Open AccessProceeding Paper

Assessment of the Optical Properties of a Graphene–Poly(3-hexylthiophene) Nanocomposite Applied to Organic Solar Cells

by Lara Velasco Davoise, Rafael Peña Capilla and Ana M. Díez-Pascual

Mater. Proc. 2021, 7(1), 22; https://doi.org/10.3390/IOCPS2021-11241 - 30 Oct 2021

Viewed by 864

Abstract

Poly(3-hexylthiophene) (P3HT) is a p-type organic semiconductor and is intrinsically a donor material. It is one of the most attractive polymers because of its high electrical conductivity and solubility in various solvents. However, its carrier mobility is considered low when compared to that [...] Read more.

Poly(3-hexylthiophene) (P3HT) is a p-type organic semiconductor and is intrinsically a donor material. It is one of the most attractive polymers because of its high electrical conductivity and solubility in various solvents. However, its carrier mobility is considered low when compared to that of inorganic semiconductors. In this work, it will be shown how the addition of different graphene (G) content tailors the principal optical and electronical parameters of P3HT, such as the conductivity, the bandgap, the hole collection properties, the carrier mobility, the refractive index, and the extinction coefficient. In particular, the conductivity, the hole collection properties and the carrier mobility are enhanced, and the bandgap is reduced with increasing graphene content. Full article

(This article belongs to the Proceedings of The 2nd International Online Conference on Polymer Science—Polymers and Nanotechnology for Industry 4.0)

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