Macromol, Volume 4, Issue 1 (March 2024) – 8 articles

The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and T_g values, indicating that higher concentrations of DEGDA resulted in lower T_g values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples. Full article

Black soldier fly larvae (BSFL) represent a way of converting organic substrates into valuable biomolecules, and are potentially exploitable as feed and food. In the present work, BSFL grown on retted hemp fiber were chemically analyzed to evaluate their nutritional profile. Chemical analysis revealed BSFL biomass to be an interesting source of proteins (40% on dry matter) rich in essential amino acids. In addition, larval biomass contained 12% fat, mainly composed of saturated fatty acids, and β-sitosterol and campesterol were found to be the most abundant among sterols. A total of 9% of the larval biomass was composed of chitin. The investigation extended to the enzymatic hydrolysis of proteins, leading to the identification of potential bioactive peptides. Peptidomics analysis coupled with in silico tools unveiled promising antioxidant, ACE-inhibitory, and DPP-IV-inhibitory properties within the protein hydrolysates. These findings revealed the potential of BSFL grown on retted hemp fiber as a source of dietary compounds as well as bioactive molecules which can be exploited as functional ingredients in the feed and food sectors. Full article

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC), and the potential use of the quaternized cellulose beads as an adsorbent was explored for the removal of humic acid (HA) from aqueous media. The introduction of quaternary ammonium groups was verified by FT-IR and XPS analyses, and their content increased to 0.524 mmol/g-Qcell by increasing the GTMAC concentration. The adsorption capacity of the HA increased with decreasing initial pH value and/or increasing content of quaternary ammonium groups, and a maximum adsorption capacity of 575 mg/g-Qcell was obtained for the quaternized cellulose beads with a content of quaternary ammonium groups of 0.380 mmol/g-Qcell. The removal % value increased with increasing dose of quaternized cellulose beads, and HA was highly removed at higher quaternary ammonium groups. The kinetics of the HA adsorption in this study followed a pseudo-second-order equation, and the process exhibited a better fit to the Langmuir isotherm. In addition, the k₂ value increased with increasing temperature. These results emphasize that HA adsorption is limited by chemical sorption or chemisorption. The quaternized cellulose beads were repetitively used for the adsorption of HA without appreciable loss in the adsorption capacity. The empirical, equilibrium, and kinetic aspects obtained in this study support that the quaternized cellulose beads can be applied to the removal of HA. Full article

Hybrid epoxide–acrylate photopolymerization enables the temporal structuring of polymer networks for advanced material properties. The ability to design polymer network architectures and to tune mechanical properties can be realized through the control of the cationic active center propagation reaction (active chain end mechanism) relative to the cationic chain transfer reaction (activated monomer mechanism). Grafted polymer networks (GPNs) can be developed through the covalent bonding of epoxide chains to acrylate chains through hydroxyl substituents, making hydroxyl-containing acrylates a promising class of chain transfer agents. This work demonstrates the formation of these GPNs and explores the physical properties obtained through the control of hydroxyl content and hybrid formulation composition. The GPNs exhibit a lower glass transition temperature than the neat epoxide network and result in a more homogeneous network. Further investigations of hydroxyl-containing acrylates as chain transfer agents will generate a wider range of physical property options for photopolymerized hybrid coatings, sealants, and adhesives. Full article

Electrospinning is a simple and affordable method of producing nanofibers, offering a large specific surface area and highly porous structures with diameters ranging from nanometers to micrometers. This process relies on an electrostatic field, providing precise control over the fiber dimensions and morphologies through parameter optimization and the use of specialized spinnerets and collectors. The paper extensively covers the electrospinning process and parameters, shedding light on the factors influencing electrospinning. It addresses the morphological and structural aspects of electrospun fibers that are used in different applications. Additionally, this paper explores various polymeric and non-polymeric materials used in electrospinning. Furthermore, it investigates the incorporation of fillers during electrospinning, using an electric field to enhance properties and functionality. The review concludes by offering insights into upscaling electrospinning production. Full article

In the present research work, calcium pimelate (CaPim) was synthesized and investigated as an additive for high-density polyethylene (HDPE). HDPE/CaPim nanocomposites were prepared by melt-mixing, with CaPim content ranging from 0.1% to 1%, affording white homogeneous materials. The chemical structure of the nanocomposites and the incorporation of CaPim was confirmed by infrared spectroscopy. The surficial morphology and the additive distribution were examined by scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction measurements showed that the thermal transitions and crystal structure of HDPE are not affected by the incorporation of CaPim, while the mechanical properties are retained overall. This study focuses on the thermal degradation of HDPE nanocomposites, investigating the degradation mechanism and kinetic parameters through various analytical methods. Isoconversional techniques, including the Friedman method, Vyazovkin analysis, and Ozawa Flynn Wall analysis, were employed to calculate activation energies (E_α). The degradation mechanism and kinetic triplet were determined based on a multivariate non-linear regression method (model-fitting). Finally, the presence of a CaPim additive was shown to increase the E_α of thermal degradation, consistent with the calculated dependence of E_α on the degree of conversion and the improved thermal stability of the HDPE matrix. Full article

Plant-based proteins are important macronutrients in the human diet, crucial for cell development in our bodies and for supporting the immune system. Given their nutritional and functional properties, plant-based proteins are excellent candidates for the development of plant-based food. Among other things, plant-based cheese has been identified as a potential enabler for future innovation through improvements in ingredient technology. Unlike traditional dairy cheeses, plant-based cheeses are made from a variety of ingredients such as nuts and legumes that can be fortified with nutrients also found in traditional cheese. Of course, plant-based cheeses still have some nutritional drawbacks, and most of them are processed, which means they contain preservatives, colour additives and high sodium content. Nevertheless, the physicochemical and functional properties of plant-based proteins are of great interest to the food industry and the initial interest in natural sources of plant proteins has recently shifted to the field of modification and processing. This review discusses the natural sources and classification of plant-based proteins and summarises recent studies on processing methods in the production of plant-based cheese. Full article

Hexakis(2-alkoxy-1,5-phenyleneimine) macrocycles were synthesized using a simple one-pot procedure through precipitation-driven cyclization. The acetal-protected AB–type monomers, 2-alkoxy-5-aminobenzaldehyde diethyl acetals, underwent polycondensation in water or acid-containing tetrahydrofuran. The precipitation–driven cyclization, based on imine dynamic covalent chemistry and π–stacked columnar aggregation, played a decisive role in the one–pot synthesis. The progress of the reaction was analyzed using MALDI–TOF mass spectrometry. The macrocycles with alkoxy chains were soluble in specific organic solvents, such as chloroform, allowing their structures to be analyzed using NMR. The shape-anisotropic, nearly planar, and shape-persistent macrocycles aggregated into columnar assemblies in polymerization solvents, driven by aromatic π-stacking. The octyloxylated macrocycle OcO–Cm6 exhibited an enantiotropic columnar liquid crystal-like mesophase between 165 °C and 197 °C. In the SEM image of (S)-(–)-3,7-dimethyloctyloxylated macrocycle (–)BCO–Cm6, columnar substances with a diameter of 200–300 nm were observed. The polymerization solution for the 2-(2-methoxyethoxy)ethoxy)ethoxylated macrocycle (TEGO–Cm6) gelled, and showed thixotropic properties by forming a hydrogen bond network. Full article