Polymer最新文献

{"title":"Ring-closing depolymerization of polyglycolide to glycolide through a synergistic transesterification strategy","authors":"Pei Zhang, Rulin Yang, Yuzhu Wang, Hongguang Sun, Guangqiang Xu, Qinggang Wang","doi":"10.1016/j.polymer.2024.127957","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127957","url":null,"abstract":"The chemical recycling of plastics to monomers provides efficient assistance for sustainable development of plastics. For polyglycolide (PGA), it has gained widespread attention to be a highly promising plastic material due to its excellent performance. However, research on the ring-closing depolymerization of PGA has yet to break through. The depolymerization is mainly limited by the challenges brought by high crystallinity and melting point of PGA, and instability of glycolide (GL). In this work, a synergistic transesterification strategy is proposed to achieve efficient depolymerization of PGA to monomer GL. Utilizing the versatile catalyst zinc bis[bis(trimethylsilyl)amide] (Zn(HMDS)2) to promote simultaneous intramolecular and intermolecular transesterification, the random chain scission and back-biting depolymerization is achieved in succession. Therefore, the depolymerization product GL can be obtained in high yield and purity. This strategy will provide new research ideas for the chemical recycling of plastics.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"14 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly flame retardant and mechanical strong polyurea through synergistic effects of aromatic dianhydride and ammonium polyphosphate","authors":"Hongyang Deng, Lixian Guo, Keping Chen, Ping Zhang, Yewei Xu, Ningning Song, Chunrong Tian, Jianhua Wang, Shuen Liang","doi":"10.1016/j.polymer.2024.127951","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127951","url":null,"abstract":"Polyurea (PUA) elastomers have gained increasing attention in both defense and civilian fields due to its remarkable mechanical properties and protective capabilities. However, its high flammability significantly limits its application in many fields. It is challenging to achieve high flame retardant rating and maintain high mechanical properties simultaneously. Synergistic combination of different types of flame retardants is essential for this purpose. Herein we report a highly efficient synergistic combination of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and ammonium phosphate (APP) for flame retardance of PUA. BTDA contributes to excellent char-forming in solid phase, and APP contributes to radical scavenging in gaseous phase. By incorporating BTDA and APP as additive flame retardants in PUA, the melt dripping in combustion was entirely suppressed, and V-0 rating in UL-94 test was achieved. The heat release rate and the release of smoke and toxic gases were greatly reduced. Meanwhile, the mechanical properties of PUA were maintained very well. The PUA composites with outstanding flame retardancy and mechanical properties may serve as ideal protective materials in a variety of applications.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"41 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvement of dielectric, processing and mechanical properties of phthalonitrile resins by copolymerisation with bismaleimide resin","authors":"Jiajia Ye, Tao Wang, Miao Wu, Shuai Zhang, Xiaobo Liu, Lifen Tong","doi":"10.1016/j.polymer.2024.127962","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127962","url":null,"abstract":"Phthalonitrile resin is an excellent material with high-temperature resistance, making it an ideal choice for a variety of high-temperature applications. However, the rapid development of the electronics industry has resulted in the emergence of more rigorous performance requirements for high-temperature resistant materials. In this study, 4,4′-bismaleimidodiphenylmethane (BDM) was used to modify benzoxazine-containing phthalonitrile resin (BAph). The results demonstrated that the incorporation of BDM resin effectively reduces the curing reactivity of phthalonitrile (PN) resin and widens the processing temperature window. Moreover, the copolymer (Poly(PN-BDM)s) exhibits excellent dimensional and thermal stability, as well as a low dielectric constant, that are, <em>CTE</em> reduces from 134 ppm/°C of Poly(PN) to 94.1 ppm/°C of Poly(PN-40BDM), <em>εr'</em> decreases to 3.22. Furthermore, the excellent interfacial adhesion between the resin matrix composites (G(PN-BDM)s) resin and the glass fibers greatly improves the mechanical properties of the G(PN-BDM)s, with more than 3 times the peel strength and more than 2 times the flexural strength and modulus.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"78 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Situ Grafted Ethylene Propylene Diene Monomer (EPDM) Rubber Multiblock Copolymers as Compatibilizers for Polyethylene (PE) and Isotactic Polypropylene (iPP) Blends","authors":"Feng Yu, Chuanjiang Long, Sitong Feng, Zhen Dong, Xiaoqing Liu, Yuanzhi Li, Zhong-Ren Chen","doi":"10.1016/j.polymer.2024.127959","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127959","url":null,"abstract":"Addressing the mounting issue of plastic waste, particularly the recycling of polyethylene (PE) and isotactic polypropylene (iPP), requires inventive and economically viable solutions. Employing compatibilizers for physical recycling is one of the most promising ways. This study utilizes reversible free radical reaction to facilitate the grafting reaction of ethylene propylene diene monomer (EPDM) between PE (or iPP) at the interface. Only 1wt.%-3wt.% EPDM is required for reactive blending, resulting in the formation of a graft multi-block copolymer that significantly improves the compatibility between PE and PP. This improvement notably enhances the mechanical properties, especially the elongation at break, which can reach up to 700%. Even after three processing cycles, the elongation at break of samples can still reach approximately 400%. The mechanism for reactive compatibilization has been supported by various characterization techniques, including tensile, rheology, peeling, and transmission electron microscope (TEM) tests. The mechanical properties of the samples were diminished when EPDM was replaced by the synthesized copolymer of ethylene and ethylidene norbornene (CEENB) and vinyl-terminated polyethylene (VPE). This observation confirms that EPDM located at the PE/iPP interface significantly contributes to the formation of grafted multi-block copolymers. Notably, the grafting reaction causes a negligible shift in the molecular weight peak, indicating minimal degradation and cross-linking of the polymers. The reversible free radical reaction involving sulfur and tetramethyl thiuramyl monosulfide (TMTM) reagents plays an important role in reducing side reactions.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"30 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional stimuli-responsive polymers on micro- and nano-patterned interfaces","authors":"Jin Ge, Eugene B. Caldona, Rigoberto C. Advincula","doi":"10.1016/j.polymer.2024.127958","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127958","url":null,"abstract":"Micro- and nano-patterned surfaces offer precise control over morphology and chemical composition, enhancing the stability, durability, and functionality of coating materials. When combined with stimuli-responsive polymers, these surfaces gain dynamic adaptability, enabling reversible binding, reusable sensing, and selective molecular capture. While recent review articles have explored various aspects of stimuli-responsive materials, from hydrogel patterns for bioanalytical applications to shape-morphing hydrogels for soft robotics and sensors, a comprehensive review focused on the integration of smart polymers with micro- or nano-patterned interfaces remains absent. This review addresses key surface patterning techniques, including soft lithography, colloidal lithography, and polymer brush photolithography, as well as advances in surface-initiated polymerization methods, such as surface-initiated controlled radical polymerization (SI-CRP). In addition, we discuss recent progress in integrating stimuli-responsive polymers with patterned surfaces to create advanced, functional materials.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"201 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ionic liquid as structuring agent of polyamide 11: Influence on the polymorphism and molecular mobility","authors":"Eva Laureys, Aurélien Roggero, Sébastien Livi, Sébastien Pruvost","doi":"10.1016/j.polymer.2024.127894","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127894","url":null,"abstract":"The impact of an imidazolium-based ionic liquid (IL) on the morphology as well as physical structure and molecular mobility of polyamide 11 (PA11) was investigated. A low IL content lead to the formation of the <span><math><mi is=\"true\">γ</mi></math></span> crystalline phase of PA11, through a fractionated crystallization process promoted by the droplet morphology obtained at the nano to microscale. The thermal and dielectric signatures of IL excess inside the droplets were evidenced. Dynamic mechanical and dielectric analyses also revealed an additional secondary <span><math><mi is=\"true\">β</mi></math></span> relaxation of PA11 associated with the mobility of its amide groups, as well as important modifications of the PA11 usual mobilities, explained by the complex interactions between the ionic liquid, water molecules and the polymer matrix.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"24 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intrinsic correlation between heterogeneous glass transition and tunable multi-shape memory effect in copolymers with pendant groups","authors":"Xiaodong Wang, Zhenghong Li, Ying Hao, Gaolei Li, Liang Xi","doi":"10.1016/j.polymer.2024.127955","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127955","url":null,"abstract":"Copolymers, which are synthesized through the statistical arrangement of two comonomers with different side chains, provide a versatile platform for the design of tunable multi-shape memory materials. However, their inherent spatial heterogeneity poses a challenge in precisely controlling the thermomechanical properties and the multi-shape memory effect (multi-SME). In this study, we propose a cooperative thermodynamic model that incorporates the concept of phase transition into the Adam-Gibbs model to address this issue. The statistical distribution of the two comonomers in the backbone is characterized using the Gaussian distribution function. By extending the Fox equation, we investigate the significant impact of composition fluctuation on local activation, heterogeneous dynamics, and the glass transition range in multi-shape memory copolymers. Furthermore, we evaluate the effectiveness of our proposed model by predicting the thermomechanical behavior and shape memory performance in copolymers with dual-, triple-, and quadruple-SMEs. The numerical results indicate that the compositional heterogeneity and the synchronized cooperative motion result in broad glass transitions in copolymers with pendant groups. Additionally, it is found that the tunable multi-SME is strongly correlated with the heterogeneous activations of local cooperative rearrangement regions. The proposed model is expected to provide theoretical guidance for the practical application of multi-shape memory copolymers.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"21 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142820604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gelation of RAFT polymer networks analysed by rheology","authors":"Patrick Imrie, Jianyong Jin","doi":"10.1016/j.polymer.2024.127956","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127956","url":null,"abstract":"Reversible addition-fragmentation chain-transfer (RAFT) polymerization is used to make polymer networks with improved homogeneity. Network formation is mostly inferred from the characterization of macro-indicators, such as vinyl bond conversion for kinetics data and swelling ratio for degree of crosslinking, which offer little information on micro-structure and homogeneity. To better probe the formation and structure of RAFT polymer networks during gelation, dynamic analysis was performed <em>in situ</em> using an advanced rheometer. In agreement with previous investigations, the time to gelation of the RAFT networks was prolonged in relation to free-radical polymerized (FRP) networks. It was found that the loss modulus (G″) of the RAFT networks was lower than that of FRP networks, indicating less friction from fewer microgel defects. The loss factor tan δ of the RAFT networks was quasi-steady, suggesting good retention of ideally elastic properties. In the vicinity of the gel point, the RAFT networks showed a prominent loss modulus (G″) local maximum phenomenon.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"46 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142820603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The injection molding of large industrial ultrahigh molecular weight polyethylene products: A microbeam WAXD/SAXS investigation of the impaction of bimodal polyethylene on the structure and mechanical properties","authors":"Shengcheng Liao, Yutao Wang, Xiangkai Mao, Minghui Wu, Zongbao Wang","doi":"10.1016/j.polymer.2024.127950","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127950","url":null,"abstract":"The injection molding of ultra-high molecular weight polyethylene (UHMWPE) large industrial products has always been a significant challenge. This study demonstrated that the addition of bimodal polyethylene (BPE) can reduce the melt viscosity of UHMWPE, enabling the injection molding of UHMWPE products with high-performance, large size, and complex shapes. Detailed analyses including microbeam wide-angle X-ray diffraction (WAXD)/small-angle X-ray scattering (SAXS), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were conducted to investigate the crystal structural differences across various regions of UHMWPE products with different BPE contents. This study revealed that those products with low BPE content exhibited larger lamellar crystal sizes and higher tensile strength, albeit with poor microstructure uniformity, resulting in low elongation at break. Conversely, products with high BPE content had more uniform microstructures but low degrees of crystal perfection, significantly improving elongation at break. Impact performance tests revealed that adding BPE did not damage the mechanical properties of UHMWPE, showing an ultra-high impact strength of 500 kJ/m². Furthermore, this study identified the significant effect of the complex flow field and molecular weight fraction of BPE on the crystal structure of the products. At low BPE concentrations, the low molecular weight portion of BPE predominated in the plasticizing effect during injection mold. Under weak flow conditions, this increased molecular chain relaxation in UHMWPE, making it difficult to maintain the oriented structure. Conversely, strong flow conditions promoted the formation of the oriented structure. However, at high BPE concentrations, the high molecular weight portion of BPE predominantly hindered the movement of UHMWPE, resulting in chain entanglement that does not improve significantly. In this context, the differences in the injection-molded samples under weak and strong flow conditions are minimal.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"3 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape Recovery Behavior and Mechanical Performance of 4D Printed Polyurethane/MWCNT Nanocomposites Under γ-Irradiation","authors":"Sivanagaraju Namathoti, Sri Ram Murthy Paladugu, Aruna Kumar Barick, P.S.Rama Sreekanth","doi":"10.1016/j.polymer.2024.127932","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127932","url":null,"abstract":"Shape memory polymers (SMPs) are a class of smart materials that are used in diverse applications and exhibit unique shape-changing abilities in response to external stimuli. Incorporating nanoparticles such as multi-walled carbon nanotubes (MWCNTs) into SMPs can further enhance their performance. However, Gamma (γ) irradiation effect on these nanocomposites remains relatively unexplored. In the current work, nanocomposite specimens were subjected to varying γ-irradiation doses of 100, 200, and 300 kGy. A comprehensive analysis was conducted to evaluate the changes in mechanical, thermal, micrographic, and shape memory behavior of the nanocomposites before and after irradiation. The results revealed a significant improvement in mechanical and thermal properties, with a 41% increase in tensile strength, a 38% increase in flexural strength, and a 11% in glass transition temperature (<em>T</em>_g) observed at the 200 kGy γ-irradiation dose. The influence of γ-irradiation on MWCNTs and their interaction with SMP was also examined. Furthermore, the shape recovery responses of strip and waveform specimens in extension and compression were investigated. It was observed that all the investigated parameters of the SMP nanocomposites showed a decline beyond an optimum irradiation dosage.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"48 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142816024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}