Article
Thermodynamics
Hechang Shi, Hongda Cheng, Changyu Han, Yanchun Yu, Mengdie Yu, Ye Zhang
Summary: This work investigates the effect of uniaxial stretching on the properties of neat poly(L-lactide) (PLLA) and miscible PLLA/poly(vinyl acetate) (PVAc) blends. The stretching process influences the thermal properties, crystallization behavior, miscibility, crystal structure, and mechanical properties of the materials. With an increased stretching ratio, the chains in PLLA and PLLA/PVAc blends become more oriented and exhibit enhanced crystallization, resulting in changes in thermal properties and improved toughness. The findings provide insight into the effect of stretching on miscible PLLA blends and offer practical implications for their large-scale application.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Biochemistry & Molecular Biology
Yunjing Chen, Lijing Han, Huiliang Zhang, Lisong Dong
Summary: This study successfully prepared highly toughened polylactide (PLA) nanocomposites with balanced stiffness and strength by modifying silica (SiO2) nanoparticles and conducting uniaxial pre-stretching. The pre-stretching process increased the elongation at break and strength while reducing the ductility gradually, indicating the effectiveness of uniaxial pre-stretching in strengthening and toughening PLA nanocomposites.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Polymer Science
Beata Misztal-Faraj, Marcelina Ciupak, Ryszard Pecherski, Leszek Jarecki
Summary: The study analyzes the development of polymorphic composition in the isothermal crystallization process of unstressed amorphous PLLA, and predicts the relationship between the transformation degree of individual polymorphs and crystallization temperature as well as the overall transformation degree.
Article
Polymer Science
Zixiong Liu, Haijun Wang, Kun Liu, Huihui Li, Xiaoli Sun, Jian Hu, Shaojuan Wang, Chunlei Yuan, Shouke Yan
Summary: A simple and efficient approach for preparing gamma-PVDF films has been developed using the spontaneous diffusion of ionic liquids into the alpha-PVDF matrix. The alpha-gamma' phase transition was found to be faster and more efficient for high-temperature prepared samples.
Article
Polymer Science
Luciana D'Urso, Maria Rosaria Acocella, Felice De Santis, Gaetano Guerra, Roberto Pantani
Summary: Biodegradable polymers, particularly poly(L-lactic acid) (PLLA), are attracting attention as an alternative to oil-based materials. However, PLLA has processing limitations due to slow melt crystallization kinetics. This study proposes the use of carbon-based nanofillers to overcome these limitations and improve the crystallization behavior of PLLA.
Article
Polymer Science
Shuangshuang Ding, Xuehui Wang, Zhigang Wang
Summary: In this study, a supertough binary PLA blend was fabricated by pre-stretching above the glass transition temperature, leading to significantly improved impact strength. Small-angle X-ray scattering and wide-angle X-ray diffraction analysis revealed that pre-stretching increased the orientation and crystallinity of PLA crystals, which greatly enhanced its toughness. This work offers a feasible and effective method to manufacture competitive PLA materials.
Article
Polymer Science
Xun Li, Min Xia, Xin Dong, Ren Long, Yuanhao Liu, Yiwan Huang, Shijun Long, Chuanqun Hu, Xuefeng Li
Summary: The structure, morphology, fracture toughness, and flaw sensitivity length scale of chain-extended poly(butylene succinate) were investigated. The results show that chain extension can significantly improve the toughness of the polymer and reduce the notch sensitivity. This principle can be applied to other high toughness material systems.
Article
Polymer Science
Tien-Wei Shyr, Huan-Chieh Ko, Tzong-Ming Wu, Meifang Zhu
Summary: The study found that different storage conditions can lead to varying levels of hydrolysis and degradation in polylactide samples, affecting their thermal stability and crystallization behavior. Hydrolysis results in shortened molecular chains, increased nucleation, decreased melting points, and increased melting enthalpy, impacting the formation of homocrystals in the samples.
Article
Polymer Science
Wenze Li, Mengyao Wang, Huan Luo, Yanhua Niu, Yajiang Huang, Guangxian Li
Summary: This study investigates the crystallization behaviors of stereocomplex and homochiral crystals by blending high molecular weight PLLA with low molecular weight PDLA and its diblock copolymers. It was found that the introduction of different sequences can inhibit the crystallization kinetics of the blends, with the formation of sc crystalites prior to hc ones. Additionally, micro phase separation between PLA and PDMS segments was observed to weaken the competition between sc and hc crystals.
Article
Polymer Science
Changchun Wang, Jia Xi Pek, Hong Mei Chen, Wei Min Huang
Summary: This study investigates the influence of temperature and strain on the toughness of dog-bone shaped poly(methyl methacrylate) (PMMA) samples through pre-stretching, and reveals the impact of aging on the sample properties.
Article
Nanoscience & Nanotechnology
Mengke Tang, Liang Jiang, Cunmin Wang, Xinyu Li, Xinjian He, Yichen Li, Changhui Liu, Yanqing Wang, Jiefeng Gao, Huan Xu
Summary: By using the parallel spinning approach, a micro/nanoscale architecture was created in electrospun PLA membranes, resulting in bimodal fibers that reduce air resistance. The addition of bone-like nanocrystalline hydroxyapatite bioelectret (HABE) enhanced the dielectric and polarization properties of the membranes, leading to improved filtration efficiency. The combination of the nanostructured electret and multistructuring strategy allows for efficient filtration and low resistance, making them highly useful for fully biodegradable filters.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Polymer Science
Suyang Dai, Ni Jiang, Zhenbo Ning, Zhihua Gan
Summary: The length of the PDLA block was found to have a significant impact on the degradation behavior of PLLA/4-DL-D blend films.
POLYMER INTERNATIONAL
(2021)
Article
Biochemistry & Molecular Biology
Wei-Wei Chang, Jinye Niu, Hui Peng, Weifeng Rong
Summary: In this study, selective formation of stereocomplex (sc) crystallization and suppression of homocrystallization (hc) in high-molecular-weight (HMW) PLLA/PDLA blends were achieved by adding C70 as a nucleator. Fourier-transformed infrared spectroscopy analysis revealed improved intermolecular interactions and inhibited molecular chain diffusion and mobility, leading to accelerated sc crystallization. The addition of C70 also resulted in a higher thermal stability compared to the neat PLLA/PDLA blend.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2023)
Article
Polymer Science
Beata Misztal-Faraj, Leszek Jarecki, Ryszard B. Pecherski
Summary: This paper formulates a kinetic model for the polymorphic crystallization of uniaxially oriented amorphous poly(L-lactide) based on the Hoffman-Lauritzen theory. The model considers the entire ranges of crystallization temperatures and amorphous orientation factor. The model predicts that the crystallization to the stable α form is controlled by the rate of transformation from the amorphous phase to α'.
Article
Materials Science, Characterization & Testing
Wenwen Zhang, Jungen Chen, Qi Yan, Qianlei Zhang, Jingyun Zhao, Tong Wu, Daoliang Wang, Lingpu Meng, Wei Chen, Liangbin Li
Summary: This study investigated the structural evolution of PET film during TD stretching with a homemade device and in-situ synchrotron radiation WAXS measurement. It was found that increasing MD pre-stretch can enhance crystallization and orientation in TD stretching. The concept of PCS cross-linked network was proposed to explain the rubber-like mechanical behavior, and an appropriate stretch ratio window above T-g was identified for inducing the PCS cross-linked network.
Article
Polymer Science
Yuanzhang Jiang, Xuyi Wang, Yanting Han, Dakai Gong, Yingchun Gu, Lin Tan
Summary: In this study, FeCl3 and poly(acrylic acid) (PAA) were doped into waterborne polyurethanes (WPUs) to create multifunctional materials with self-healing and antimicrobial properties. WPU/Fe/PAA-5.5, containing 5.5 wt % PAA, exhibited excellent mechanical properties, strong self-healing capabilities, and an impressive antimicrobial rate of over 90%. These supramolecular films were also highly recyclable through hot-pressing.
Article
Polymer Science
Longyu Tian, Min Wang, Guangming Liao, Baoliang Liu, Sujuan Zhang, Yucheng Sun, Zhen Meng, Jintao Zhang, Zaijun Lu
Summary: Two kinds of benzoxazine monomers were synthesized and used to prepare polybenzoxazine anion exchange membranes (AEMs) with quaternary ammonium functionalization. The LQPBZ AEM exhibited better ion conductivity and alkaline stability.
Article
Polymer Science
Claire A. Lemarchand
Summary: This study investigates the shock behavior of three different polymers through molecular dynamics simulations. The results reveal specificities in the shock behavior of polymers, including deviations from the linear relation between shock velocity and particle velocity, as well as differences in shear stress relaxation behind the shock front. It is found that the deviation of the Hugoniot locus is related to the change in the relative contribution of bonding and non-bonding potential energies, while polymers with higher glass transition temperatures exhibit slower shear stress relaxation.
Article
Polymer Science
Zengquan Liu, Xiaochun Yin, He Zhang, Shuo Gao, Qinglin Kuang, Yanhong Feng
Summary: A powder solid-state extension (PSSE) technology was proposed to address the high melt viscosity issue of UHMWPE. By uniaxial extension and sintering in the solid state, a highly self-reinforced material was prepared. X-ray diffraction and scattering techniques were used to study the structural evolution during the PSSE process, and a solid-phase induced transformation model was established.
Article
Polymer Science
Zhike Li, Anyu Luo, Rui Zhou, Xin Li, Haiyan Li
Summary: A novel high temperature resistance IL@SiO2 nanocapsules were successfully prepared and their friction and wear properties in PA6 composites were studied. The addition of IL@SiO2 nanocapsules reduced the friction coefficient and wear rate without affecting the mechanical properties of PA6. The synergy between the IL core and SiO2 wall in the nanocapsules improved the self-lubricating performance of the PA6 composites.
Article
Polymer Science
Xin Liu, Xuhong Guo, Qi Liao
Summary: In this study, an algorithm for accurately estimating viscosity is developed using molecular dynamics simulations and the Green-Kubo formula. This algorithm can be applied to complex systems with long correlations, such as macromolecular and biological simulation systems.
Article
Polymer Science
Hao Pu, Yun-Lei Hou, Jing -Zhou Chen, Dong -Lin Zhao
Summary: The use of modified graphene improves the interfacial adherence of carbon fibers to epoxy resin, resulting in enhanced interfacial and bending properties of CF and matrix in CF/EP composites, as well as increased interlaminar shear strength and flexural strength.
Article
Polymer Science
Wei-Chung Ke, Jin-Wei Lin, Manohar Reddy Busireddy, Yueh-Hsing Lee, Jiun-Tai Chen, Chain-Shu Hsu
Summary: This study introduces a crosslinkable monomer, TAIC, to synthesize three crosslinked polyimide films, which exhibit improved thermal, mechanical, and dielectric properties. The introduction of TAIC enhances the tensile strength, reduces the dielectric constant and dielectric loss, and decreases the coefficient of thermal expansion of the polyimide films.
Article
Polymer Science
Alex Kwasi Kumi, Ruiling Fan, Ye Chen, Yumei Zhang
Summary: The difference in leaching of amylopectin from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) blends during regeneration in water and aqueous ethanol has been studied. Molecular dynamics simulations showed that the dissolution and regeneration mechanisms of amylopectin in [Bmim][Cl] are similar to cellulose in ionic liquids. Water regeneration leads to weak electrostatic interactions, resulting in high leaching of amylopectin. In contrast, ethanol-water interactions enhance electrostatic interactions among amylopectin chains, limiting amylopectin leaching in aqueous ethanol.
Article
Polymer Science
Xi Zeng, Junwei Zhou, Junbiao Peng, Chunsheng Zhang, Danling Wang, Yihu Song, Qiang Zheng
Summary: This study utilizes an oligomer deep eutectic solvent (DES) based on polyethylene glycol to regulate the vulcanization kinetics of rubber. The results show that the DES can accelerate vulcanization at low temperatures without affecting the crosslinking density and Mullins effect.
Article
Polymer Science
Qianqian Yue, Yongfei Peng, Xingjian Liu, Aihua He, Huarong Nie
Summary: The addition of metal deactivators can effectively suppress the aging of TBIR, prolong its lifespan, and have no negative effects on its physical and processing properties. These research findings are of great importance for improving the stability and aging resistance of polymers.
Article
Polymer Science
J. Gomez-Caturla, J. Ivorra-Martinez, R. Tejada-Oliveros, V Moreno, D. Garcia-Garcia, R. Balart
Summary: This work focuses on the development of environmentally friendly PLA formulations by using different esters derived from geraniol as plasticizers. The results show that these esters have good compatibility with PLA, and they can effectively enhance the elongation and plasticity of PLA, reduce its glass transition temperature, and slightly improve its water absorption capabilities.
Article
Polymer Science
Dandan Li, Zhaohui Lu, Zhao Ke, Ke Xu, Fengna Dai, Youhai Yu, Guangtao Qian, Chunhai Chen
Summary: In this study, cross-linked PI aerogel membranes with low dielectric constant and high moisture resistance were prepared by co-polymerization and scraping coating technology. The incorporation of fluorinated blocks and benzimidazole ring structures resulted in novel PI aerogel membranes with fascinating dielectric properties and outstanding moisture resistance.
Article
Polymer Science
Zhaoyang Chu, Qing Zhang, Haihua Luo, Han Zhou, Fapei Zhang, Wei Chen, Wenhua Zhang
Summary: Multi-physical fields solution processing strategy is a universal and facile method for preparing various conjugated polymer films and high-performance devices. In this study, we employed a combined microfluidic flow and ultrasonication strategy (FU) for processing CP solutions, and found a pronounced synergetic effect in promoting the pre-ordering of chains in solution. The conformation order and anisotropy of the solution were revealed through various characterizations. A non-classical nucleation model for polymer crystallization in non-equilibrium solution processing was confirmed. The roles of microfluidic flow and ultrasonication in chain aggregation and crystallization were addressed through multi-physical simulations. Compared to pristine solutions, the FU strategy showed improved solution anisotropy and crystallization kinetics, resulting in higher crystallinity in films and increased mobilities in OFET devices. The FU processing strategy provides a universal approach for regulating chain conformation and aggregation in conjugated polymer solutions.