Polymers

Research

12 pages, 5817 KiB

Open AccessArticle

Fire-Resistant and Thermal Stability Properties of Fluorosilicone Adhesives by Incorporation of Surface-Modified Aluminum Trihydrate

by Kyung-Soo Sung, Hye-Won Cho, Dae-Ho Lee, Woonjung Kim and Namil Kim

Polymers 2024, 16(17), 2510; https://doi.org/10.3390/polym16172510 - 4 Sep 2024

Viewed by 380

Abstract

Fluorosilicone was combined with aluminum trihydrate (ATH) to induce synergistic flame-retardant and thermal-resistant properties. The surface of ATH was modified with four different silane coupling agents. The flammability and mechanical properties of the fluorosilicone/ATH composites were assessed using an UL94 vertical test and [...] Read more.

Fluorosilicone was combined with aluminum trihydrate (ATH) to induce synergistic flame-retardant and thermal-resistant properties. The surface of ATH was modified with four different silane coupling agents. The flammability and mechanical properties of the fluorosilicone/ATH composites were assessed using an UL94 vertical test and a die shear strength test. The change in shear strength was investigated under aging for 1000 h at −55 °C and 150 °C. Pure fluorosilicone had inherent fire resistance and thus achieved a V-0 rating even at 20 wt.% ATH loading. Upon addition of ATH treated with 3-glycidoxypropyl trimethoxysilane, the composites exhibited the highest shear strength of 3.9 MPa at 23 °C because of the additional crosslinking reaction of fluorosilicone resin with the epoxide functional group of the coupling agent. Regardless of the types of coupling agents, the composites exhibited similar flame retardancy at the same ATH content, with a slight reduction in shear strength at 180 °C and 250 °C. The shear strength of the adhesives gradually decreased with aging time at −55 °C, but increased noticeably from 3.9 MPa to 11.5 MPa when aged at 150 °C due to the occurrence of the additional crosslinking reaction of fluorosilicone. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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11 pages, 2024 KiB

Open AccessArticle

Revealing the Impact of Viscoelastic Characteristics on Performance Parameters of UV-Crosslinked Hotmelt Pressure-Sensitive Adhesives: Insights from Time–Temperature Superposition Analysis

by Marian Guder, Roman Günther, Katharina Bremgartner, Nicole Senn and Christof Brändli

Polymers 2024, 16(15), 2123; https://doi.org/10.3390/polym16152123 - 25 Jul 2024

Viewed by 649

Abstract

This study emphasizes the influential role of rheology in decoding the viscoelastic properties of pressure-sensitive adhesives (PSAs) vital to predicting key application features such as shear, tack, and peel, depending on the flow characteristics of PSAs during bonding and debonding processes. By applying [...] Read more.

This study emphasizes the influential role of rheology in decoding the viscoelastic properties of pressure-sensitive adhesives (PSAs) vital to predicting key application features such as shear, tack, and peel, depending on the flow characteristics of PSAs during bonding and debonding processes. By applying the principle of time–temperature superposition (TTS), we extend the scope of our frequency analysis, surpassing the technical constraints of the available apparatus. Our exploration aims to uncover the general correlations between PSAs’ viscoelastic properties and their performance in end-use applications. Initially, the adhesive performance and viscoelastic properties of a UV-crosslinkable styrene-butadiene-styrene (SBS) model adhesive prior and subsequent to UV irradiation were examined. The subsequent crosslinking reaction increased cohesive strength and heat resistance, although tack and peel strength observed a substantial decline. We successfully demonstrated these effects by logging the viscoelastic properties, specifically the storage modulus G′ at lower frequencies, which mirrors the shear strength at higher temperatures and the shift in the tan δ peak to represent each PSA’s tack. These correlations were partially reflected in three commercial UV crosslinkable acrylic PSA products, although the effect of UV irradiation was less distinctive. This study also revealed the challenges in predicting tack and peel strength, which result from a complex interplay of bonding and debonding processes. Our findings reinforce the necessity for more sophisticated analysis techniques and models that can accurately predict the end-use performance of PSAs across different physical structures and chemical compositions. Further research is needed to develop these predictive models, which may reduce the need for labor-intensive testing under real-life conditions. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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18 pages, 4130 KiB

Open AccessArticle

Environmental Bond Degradation of Different Laminated Glass Panels

by Alaa El-Sisi, Mohamed Elsawi Mahmoud, Hesham El-Emam, Ahmed Elbelbisi and Hani Salim

Polymers 2024, 16(14), 2040; https://doi.org/10.3390/polym16142040 - 17 Jul 2024

Viewed by 480

Abstract

Since buildings are designed to endure over time, it is crucial to comprehend how laminated glass (LG) windows, and consequently, the polymer interlayer materials, respond to weathering. This paper explores the impact of accelerated humidity on the mechanical properties of several polymer interlayer [...] Read more.

Since buildings are designed to endure over time, it is crucial to comprehend how laminated glass (LG) windows, and consequently, the polymer interlayer materials, respond to weathering. This paper explores the impact of accelerated humidity on the mechanical properties of several polymer interlayer materials and LG sections. The study specifically focuses on three polymer interlayer materials of industrial interest: polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), and ionomer (SG). To examine the environmental effects, testing setups were devised to subject the polymeric materials and LG panels to specific conditions. Uniaxial tension coupons and LG disks were submerged in a water bath to simulate the environmental effect. A dedicated testing fixture was designed and manufactured for the LG disks. The results showed that the properties of EVA, including strength, maximum strain, and toughness, were not significantly affected by the environmental conditions. However, the properties of SG5000 were notably impacted, with a significant reduction in its bond strength due to water immersion. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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17 pages, 5738 KiB

Open AccessArticle

Effect of Synthetic Low-Odor Thiol-Based Hardeners Containing Hydroxyl and Methyl Groups on the Curing Behavior, Thermal, and Mechanical Properties of Epoxy Resins

by Young-Hun Kim, Jeong Ju Baek, Ki Cheol Chang, Baek Soo Park, Won-Gun Koh and Gyojic Shin

Polymers 2023, 15(13), 2947; https://doi.org/10.3390/polym15132947 - 4 Jul 2023

Cited by 1 | Viewed by 2127

Abstract

A novel thiol-functionalized polysilsesqioxane containing hydroxyl and methyl groups was synthesized using a simple acid-catalyzed sol–gel method to develop an epoxy hardener with low odor, low volatile organic compound (VOC) emissions, and fast curing at low temperatures. The synthesized thiol-based hardeners were characterized [...] Read more.

A novel thiol-functionalized polysilsesqioxane containing hydroxyl and methyl groups was synthesized using a simple acid-catalyzed sol–gel method to develop an epoxy hardener with low odor, low volatile organic compound (VOC) emissions, and fast curing at low temperatures. The synthesized thiol-based hardeners were characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and gel permeation chromatography and compared with commercially available hardeners in terms of odor intensity and VOC emissions using the air dilution olfaction method and VOC analysis. The curing behavior and thermal and mechanical properties of the epoxy compounds prepared with the synthesized thiol-based hardeners were also evaluated. The results showed that synthetic thiol-based hardeners containing methyl and hydroxyl groups initiated the curing reaction of epoxy compounds at 53 °C and 45 °C, respectively. In contrast, commercial thiol-based hardeners initiated the curing reaction at 67 °C. Additionally, epoxy compounds with methyl-containing synthetic thiol-based hardeners exhibited higher TGA at a 5% weight loss temperature (>50 °C) and lap shear strength (20%) than those of the epoxy compounds with commercial thiol-based hardeners. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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14 pages, 3813 KiB

Open AccessArticle

Synthesis and Evaluation of Metal Lipoate Adhesives

by Animesh Ghosh, Konrad Kozlowski and Terry W. J. Steele

Polymers 2023, 15(13), 2921; https://doi.org/10.3390/polym15132921 - 1 Jul 2023

Viewed by 1545

Abstract

The development of new bioadhesives with integrated properties remains an unmet clinical need to replace staples or sutures. Current bioadhesives do not allow electronic activation, which would allow expansion into laparoscopic and robotic surgeries. To address this deficiency, voltage-activated adhesives have been developed [...] Read more.

The development of new bioadhesives with integrated properties remains an unmet clinical need to replace staples or sutures. Current bioadhesives do not allow electronic activation, which would allow expansion into laparoscopic and robotic surgeries. To address this deficiency, voltage-activated adhesives have been developed on both carbene- and catechol-based chemical precursors. Herein, a third platform of voltage-activated adhesive is evaluated based on lipoic acid, a non-toxic dithiolane found in aerobic metabolism and capable of ring-opening polymerization. The electro-rheological and adhesive properties of lithium, sodium, and potassium salts of lipoic acid are applied for wet tissue adhesion. At ambient conditions, potassium lipoate displays higher storage modulus than lithium or sodium salt under similar conditions. Voltage stimulation significantly improves gelation kinetics to Na- and K-lipoates, while Li-lipoate is found to not require voltage stimulation for gelation. Lap shear adhesion strength on wetted collagen substrates reveals that the synthetic metal lipoates have comparable adhesion strength to fibrin sealants without viral or ethical risks. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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14 pages, 5907 KiB

Open AccessArticle

Proposal of Evaluation Method for Crack Propagation Behaviors of Second-Generation Acrylic Adhesives under Mode I Static Loading

by Yuki Ogawa, Kimiyoshi Naito, Keisuke Harada and Hiroyuki Oguma

Polymers 2023, 15(8), 1878; https://doi.org/10.3390/polym15081878 - 14 Apr 2023

Cited by 2 | Viewed by 1202

Abstract

Second-generation acrylic (SGA) adhesives, possessing high strength and toughness, are applicable in automotive body structures. Few studies have considered the fracture toughness of the SGA adhesives. This study entailed a comparative analysis of the critical separation energy for all three SGA adhesives and [...] Read more.

Second-generation acrylic (SGA) adhesives, possessing high strength and toughness, are applicable in automotive body structures. Few studies have considered the fracture toughness of the SGA adhesives. This study entailed a comparative analysis of the critical separation energy for all three SGA adhesives and an examination of the mechanical properties of the bond. Loading-unloading test was performed to evaluate crack propagation behaviors. In the loading–unloading test of the SGA adhesive with high ductility, plastic deformation was observed in the steel adherends; the arrest load dominated the propagation and non-propagation of crack for adhesive. The critical separation energy of this adhesive was assessed by the arrest load. In contrast, for the SGA adhesives with high tensile strength and modulus, the load suddenly decreased during loading, and the steel adherend was not plastically deformed. The critical separation energies of these adhesives were assessed using the inelastic load. The critical separation energies for all the adhesives were higher for thicker adhesive. Particularly, the critical separation energies of the highly ductile adhesives were more affected by the adhesive thickness than highly strength adhesives. The critical separation energy from the analysis using the cohesive zone model agreed with the experimental results. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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12 pages, 2682 KiB

Open AccessArticle

Influence of Sulfododecenylsuccinylation on the Adhesion to Fibers and Film Properties of Corn Starch for Warp Sizing

by Chaohui Zhang, Wei Li and Zhenzhen Xu

Polymers 2023, 15(6), 1495; https://doi.org/10.3390/polym15061495 - 17 Mar 2023

Viewed by 1131

Abstract

To improve the film brittleness and adhesion to fibers of dodecenylsuccinated starch (DSS), DSS samples were sulfonated with excess NaHSO₃ to prepare a series of sulfododecenylsuccinated starch (SDSS) samples with different degrees of substitution (DS). Their adhesion to fibers, surface [...] Read more.

To improve the film brittleness and adhesion to fibers of dodecenylsuccinated starch (DSS), DSS samples were sulfonated with excess NaHSO₃ to prepare a series of sulfododecenylsuccinated starch (SDSS) samples with different degrees of substitution (DS). Their adhesion to fibers, surface tensions, film tensile properties and crystallinities, and moisture regains were studied. The results showed that the SDSS was superior to DSS and acid-thinned starch (ATS) in the adhesion to cotton and polyester fibers and breaking elongation of film but was inferior to them in tensile strength and degree of crystallinity of film, which revealed that sulfododecenylsuccination could further improve the adhesion of ATS to both fibers and reduce its film brittleness compared to starch dodecenylsuccination. With the increase in the DS, the adhesion to both fibers and the film elongation of SDSS gradually increased and then decreased, while its film strength consistently decreased. Considering adhesion and film properties, the SDSS samples with a DS range of 0.024-0.030 were recommended. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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13 pages, 3848 KiB

Open AccessArticle

Investigation of Ferromagnetic and Ferroelectric Properties in Binderless Cellulose/Ni Laminates for Magnetoelectric Applications

by Manseong Song and Su-Chul Yang

Polymers 2022, 14(24), 5347; https://doi.org/10.3390/polym14245347 - 7 Dec 2022

Viewed by 1457

Abstract

According to reported polymer-based magnetoelectric (ME) laminates, which generate voltage via an external magnetic field, a binder is indispensable for the adhesion between phases. However, if the binder is excluded, the ME response is expected to improve via efficient strain transfer from the [...] Read more.

According to reported polymer-based magnetoelectric (ME) laminates, which generate voltage via an external magnetic field, a binder is indispensable for the adhesion between phases. However, if the binder is excluded, the ME response is expected to improve via efficient strain transfer from the magnetostrictive phase to the piezoelectric phase. Nevertheless, an understanding of the binderless state has not yet been addressed in polymer-based ME laminates. In this study, cellulose/Ni (CN) laminates were designed to obtain binderless polymer-based ME laminates. The surface properties of Ni foil desirable for the anchoring effect and the electrostatic interactions required for binderless states were determined via heat treatment of the Ni substrate. Moreover, to confirm the potential of the binderless laminate in ME applications, the ferromagnetic and ferroelectric properties of the CN laminates were recorded. Consequently, the CN laminates exhibited remnant and saturation magnetizations of 29.5 emu/g and 55.2 emu/g, respectively. Furthermore, the significantly increased remnant and saturation polarization of the CN laminates were determined to be 1.86 µC/cm² and 0.378 µC/cm², an increase of approximately 35-fold and 5.56-fold, respectively, compared with a neat cellulose film. The results indicate that multiferroic binderless CN laminates are excellent candidates for high-response ME applications. Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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21 pages, 3756 KiB

Open AccessArticle

Hot-Melt and Pressure-Sensitive Adhesives Based on Styrene-Isoprene-Styrene Triblock Copolymer, Asphaltene/Resin Blend and Naphthenic Oil

by Sergey O. Ilyin, Viktoria Y. Melekhina, Anna V. Kostyuk and Nina M. Smirnova

Polymers 2022, 14(20), 4296; https://doi.org/10.3390/polym14204296 - 13 Oct 2022

Cited by 7 | Viewed by 3825

Abstract

Asphaltene/resin blend (ARB) extracted from heavy crude oil was used to modify poly(styrene-block-isoprene-block-styrene) (SIS) to make it an adhesive. There were prepared double and triple mixtures containing 10–60% SIS, 10–40% ARB, and 10–50% naphthenic oil used as an additional plasticizer. The viscoelasticity of [...] Read more.

Asphaltene/resin blend (ARB) extracted from heavy crude oil was used to modify poly(styrene-block-isoprene-block-styrene) (SIS) to make it an adhesive. There were prepared double and triple mixtures containing 10–60% SIS, 10–40% ARB, and 10–50% naphthenic oil used as an additional plasticizer. The viscoelasticity of the mixtures at 25 °C and 120 °C was studied, their flow curves were obtained, and the temperature dependences of the loss tangent and the components of the complex modulus were measured. In addition, the mixtures were used as hot-melt adhesives (HMAs) and pressure-sensitive adhesives (PSAs) in the shear, peel, and pull-off tests of the adhesive bonds that they formed with steel. Both naphthenic oil and ARB act as plasticizers for SIS and make it sticky. However, only the combined use of ARB and the oil allows for achieving the best set of adhesive properties of the SIS-based mixture. High-quality HMA requires low oil content (optimal SIS/ARB/oil ratio is 50/40/10, pull-off adhesion strength (τ_t) of 1990 kPa), whereas a lot of the oil is needed to give SIS characteristics of a PSA (SIS/ARB/oil is 20/40/40, τ_t of 100 kPa). At the same time, the resulting PSA can be used as a hot-melt pressure-sensitive adhesive (HMPSA) that has many times lower viscosity than HMA (13.9 Pa·s versus 2640 Pa·s at 120 °C and 1 s⁻¹) but provides a less strong adhesive bond (τ_t of 960 kPa). Full article

(This article belongs to the Special Issue Research and Application of Polymer Adhesives)

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