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¹H NMR spectra of PGMA polymer with different molecular weight a PGMA–1 (L), b PGMA–2 (M), and c PGMA–3 (H). Low, medium, and high of molecular weight are abbreviated in L, M, and H, respectively
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Recycled poly(ethylene terephthalate) (r-PET) is a thermoplastic polyester. Repeated heat processing of r-PET may negatively affect physical properties due to thermal degradation. Therefore, to improve the physical properties of r-PET, poly(glycidyl methacrylate) (PGMA) samples with different molecular weights (low, medium, and high) were synthesiz...
Citations
... However, its rigid chemical structure negatively impacts performance due to its low toughness characteristics. Therefore, there have been various studies to improve its properties through copolymerization and modification [40][41][42][43][44][45][46][47]. By introducing dynamic covalent crosslinking to the aliphatic polymer structure, the mechanical properties of the materials could be improved while maintaining plasticity and recyclability to a certain extent. ...
This article reports a potential high-value reuse pathway for a depolymerized vitrimer matrix from abandoned composites. A series of polyethylene terephthalate (PET)-based copolymers containing various amounts of added vitrimer as the toughness modifier were synthesized by melt polymerization. The thermal, mechanical, and crystallization behaviors of the synthesized copolymers were determined, indicating all samples presented excellent thermal stability at Td-5% above 390 °C. The differential scanning calorimetry and wide-angle X-ray scattering diffraction results demonstrated that the copolymers maintained the crystallization characteristics of normal PET, while a slight reduction in the crystallizability was observed upon the incorporation of the vitrimer. Moreover, the mechanical behaviors of the copolymers were investigated systematically. Surprisingly, a significant increment was observed in the elongation rate from 11.1 to 804.2% when the added vitrimer content increased from 0 to 0.25 wt%, and this trend decreased slightly as the vitrimer content increased further. Impact strength examinations revealed twofold enhancement as the vitrimer concentration increased from 0 to 0.25 wt%, with further improvement as the content was increased. The shore D hardness test illustrated that all samples showed comparable values at around 80, suggesting that introducing the vitrimer does not decrease the hardness of the PET-based copolymers.
... The rugged surface contour of PET enhances the inter-fiber friction and enhances the tensile characteristics of blended r-PET structures. [77] In several literatures r-PET yarns and fabric structures have been employed with cotton, [77,78] virgin PET, [78,79] viscose, [80] polyglycidyl mythacrylate- [81] and wool . [82] Higher surface roughness may be advantageous for generating a locked structure, but it has a detrimental impact on hand value [83] and luster of the textile ensemble. ...
The rising significance of the circular economy as a strategy for sustainable growth in the synthetic polymer sector has led researchers to suggest several blue ocean techniques to create new demand. Polyethylene terephthalate, a promising synthetic polymer used in textiles and packaging, contributes to unmanageable amounts of post-consumer trash. The ban on single-use plastics (SUP) forced researchers to find the best “circularity” path using the 5 R framework. By analyzing multiple recycling methods it is inferred that recycling of the post-consumer polyester waste is the best option to achieve sustainability based on United Nation’s Sustainable Development Programme.
... Generally, coarse unstable phase morphologies are observed in simple blends of various polymers because most polymer blends are thermodynamically immiscible, leading to deterioration of interphase adhesion, interfacial thickness and mechanical properties. All these issues can be addressed through the introduction of several additives, often known as compatibilizer, which are usually block and graft copolymers, by which compatibility and properties of the blend is greatly enhanced [14,16,17]. Such compatibilization generally leads to stabilized morphology possessing a fine dispersion of the minor phase, by which the macroscopic properties of the blend are significantly affected, arising from the fact that they have tendency to concentrate at the interface as emulsifiers [15,18]. ...
In this research work, polyethylene terephthalate (PET) and polystyrene (PS) were melt blended using glycidyl methacrylate-grafted styrene-block-butadiene (SbB-g-GMA) as a dual functional reactive compatibilizer and impact modifier to achieve a blend with stable morphology having no distinct phase separation. Accordingly, for the fabrication of the dual functional reactive compatibilizer, copolymerization was conducted through grafting glycidyl methacrylate (GMA) onto styrene-block-butadiene copolymer (SbB). Then, different compositions of the blends were prepared with various loadings of the compatibilizer. It was demonstrated that blending of PET with PS compatibilized with dual purpose compatibilizer resulted in a blend with improved toughness, thermal and mechanical properties as compared to the uncompatibilized blend. Moreover, it was demonstrated by the field- emission scanning electron microscopy (FE-SEM) results that although the unmodified PET/ PS blend was composed of large PS droplets, the PS droplets size was significantly minimized in the compatibilized blends, indicating better miscibility, and therefore, superior mechanical properties. The results demonstrate the effectiveness of the developed dual-functional compatibilizer for potential recycling of PET and PS, as two widely consumed polymers via a simple melt blending approach. The compatibilized blends with improved properties have great potential for use in a variety of applications.
... However, these plastic products required several hundred years to fully decay into the soil [9]. Furthermore, their collection and storage for recycling is an undesirable and time-consuming process [10]. A viable strategy is to develop bio-based polymer materials as alternatives to these materials to minimize Polymers 2022, 14,1952 2 of 19 the use of non-biodegradable polymers [11][12][13][14][15]. Considering these, the key to biodegradable polymer-based foams can be used in a wide range of applications, owing to their biocompatibility [16,17], biodegradability, and renewability process [18]. ...
Starch-based biodegradable foams with a high starch content are developed using industrial starch as the base material and supercritical CO2 as blowing or foaming agents. The superior cushioning properties of these foams can lead to competitiveness in the market. Despite this, a weak melting strength property of starch is not sufficient to hold the foaming agents within it. Due to the rapid diffusion of foaming gas into the environment, it is difficult for starch to maintain pore structure in starch foams. Therefore, producing starch foam by using supercritical CO2 foaming gas faces severe challenges. To overcome this, we have synthesized thermoplastic starch (TPS) by dispersing starch into water or glycerin. Consecutively, the TPS surface was modified by compatibilizer silane A (SA) to improve the dispersion with poly(butylene adipate-co-terephthalate) (PBAT) to become (TPS with SA)/PBAT composite foam. Furthermore, the foam-forming process was optimized by varying the ratios of TPS and PBAT under different forming temperatures of 85 °C to 105 °C, and two different pressures, 17 Mpa and 23 Mpa were studied in detail. The obtained results indicate that the SA surface modification on TPS can influence the great compatibility with PBAT blended foams (foam density: 0.16 g/cm3); whereas unmodified TPS and PBAT (foam density: 0.349 g/cm3) exhibit high foam density, rigid foam structure, and poor tensile properties. In addition, we have found that the 80% TPS/20% PBAT foam can be achieved with good flexible properties. Because of this flexibility, lightweight and environment-friendly nature, we have the opportunity to resolve the strong demands from the packing market.
... In order to achieve better recovery properties of rPET, a series of copolymers with epoxy functional groups were also synthesized [35][36][37][38]. Benvenuta Tapia et al. synthesized a series of copolymers, e.g., a triblock polymers with middle block of poly(styreneacrylonitrile) and two end blocks of poly(styrene-glycidyl methacrylate) (SGMA-SAN-SGMA), a triblock polymer with a middle block of poly(butyl acrylate) and extreme blocks of poly(styrene-glycidyl methacrylate) (SGMA-BA-SGMA) and a random copolymer of glycidyl methacrylate and styrene (GMS-ran-S) as a chain extender for polyester via reversible addition-fragmentation transfer (RAFT) and nitroxide mediated polymerization (NMP), respectively [39][40][41][42][43][44][45]. ...
Annual production of textile fibers is continuing to rise and the substantial discharge of undegradable waste polyester fibers can cause serious environmental and even health problems. Thus, the recycling and reuse of recycled poly(ethylene terephthalate) from waste textiles (rPET-F) is highly desirable but still challenging. Here, five chain extenders with a different number of epoxy groups per molecules were used to blend with discarded PET fibers and improve its viscosity and quality loss in the recycling process. The molecule weight, thermal properties, rheological properties and macromolecular architecture of modified r-PET were investigated. It was found that all modified rPET-F samples show higher viscosities and better thermal properties. rPET-F modified by difunctional EXOP molecules show linear structure and improved rheological properties. rPET-F modified by polyfunctional commercial ADR and synthesized copolymers exhibit a long chain branched structure and better crystallization. This study reveals a deeper understanding of the chain extension and opens an avenue for the recycling of PET textiles.
... Among the most common functional groups that can react with the carboxyl and hydroxyl terminals of PET are isocyanates [6,13], anhydrides [11,[14][15][16], epoxies [9,11,14,[17][18][19] and phosphites [15,20,21]. Particularities in relation to the reactivity of each of these structures can allow the formation of more extensive chains, whether branched or linear [22]. ...
... Chen et al. [18] and Benvenuta et al. [19] investigated the effects of glycidyl methacrylate (GMA) from different molar Molar mass increase may be associated with crosslinking formation, as described in some studies [46,[50][51][52]. Crosslinking is known to occur due to the reaction of thermo-oxidative degradation products or through polycarbodiimide reactions. ...
Poly(ethylene terephthalate) is one of the most used polymers in the world that results in tons disposed in landfills and dumping grounds. Despite the advantages of using recycled PET, the recycling process decrease its physical-chemical properties. The present study addresses the use of polycarbodiimide-based additive to increase the molar mass of post-consumer PET. A new approach is proposed to evaluate the molar mass, as well as the relationship between the intrinsic viscosity and oscillatory rheometry. This analysis allowed us to compare the measurement obtained in diluted solution and melt from complex viscosity out of the Newtonian plateau. Different concentrations of additive in the post-consumer (dry or wet) PET reprocessing resulted in materials with different molar mass ranges. Consequently, different market applications will be available, such as textile fiber, bottles or engineering goods.
Graphic Abstract
... Chen et al. [15] estudaram o efeito da adição do polímero PGMA, que contêm o grupo reativo -GMA, no comportamento térmico, mecânico e reológico do PET reciclado. Os autores observaram não só um aumento na rigidez com o aumento da temperatura de transição vítrea (T g ), provocado pela presença do PGMA, mas também verificaram que as blendas formuladas aumentaram a viscosidade do fundido no processamento, favorecendo o seu uso em aplicações na reciclagem de PET como embalagens, fios ecológicos e tecidos não tecidos (TNT). ...
Resorcinol has been classified as an organic pollutant that can cause serious health problems and can even lead to death. Resorcinol is present in the wastewater discharged by many industries and thus threatens the normal life of living beings. In the present work a novel material based on polyvinyl chloride (PVC), glycidyl methacrylate (GMA) and hexamethylenediamine (HDA) was prepared and used as an adsorbent for resorcinol removal from water. GMA was grafted onto PVC by an atom transfer radical polymerization (ATRP) using iodinated PVC (PVC-I) as a macroinitiator. Afterward, the resulting PGMA-g-PVC graft copolymer was functionalized by HDA. The removal of resorcinol using the developed material was carried out by the adsorption process; the obtained results showed that the adsorbent had a maximum adsorption capacity of 943.4 mg/g. In addition, the experimental data revealed that the adsorption process was well-fitted by the pseudo-second-order kinetic model, which indicates the dominance of chemisorption in the adsorption process. Moreover, the developed adsorbent showed good selectivity toward resorcinol in comparison with phenolic products like phenol, hydroquinone and bisphenol A. The synthesized copolymers were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD).
