INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Zhen Zhang,Shanlin Cui,Ruixue Ma,Qiuyang Ye,Jiahui Sun,Yaming Wang,Chuntai Liu,Zhen Wang
High-toughness biodegradable poly(lactic acid) (PLA) has always been intensively pursued on the way of replacing traditional petroleum-based plastics. Regulating microstructures to achieve self-toughening holds great promise due to avoidance of incorporating other heterogeneous components. Herein, we propose a straightforward and effective way to tailor microstructures and properties of PLA through melt-stretching and quenching of slightly crosslinked samples. The melt stretching drives chains orientation and crystallization at high temperature, while the quenching followed can freeze the crystallization process to any stage. For the first time, we prepare a type of transparent and low-crystalline PLA filled with rod-like β-form shish, which displays an outstanding tensile toughness, almost 17 times that of the conventional technique-processed one. This mechanical superiority is enabled by an integration of high ductility due to oriented chain network, and high tensile stress endowed by nanofibrous filler's role of β-form shish. Furthermore, the mechanically toughened PLA is demonstrated to generate the richest micro-cracks and shear bands under loading, which can effectively dissipate the deformational energy and underlie the high toughness. This work opens a new prospect for the bottom-up design of high-performance bio-based PLA materials that are tough, ductile and transparent by precise microstructural regulation through scalable melt processing route.
研究领域:
材料科学
·
生物降解材料
·
高分子物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2018
·Vol. 132
·期 2
·947-953
·
IF 2.209
Dai Xin,Wang Zhenxi,Zhang Xiaohang,Xu Sheng,Zhang Shangxi,Cao Meng,Jiang Xinde
To obtain multi-functional β-iPP composites, β-iPP composites are always filled by multiple fillers with α-nucleating ability. To prepare β-iPP/TiO 2 /MMT composites, TiO 2 -supported MMT with a β-nucleating surface was prepared through hydrolysis reaction of Tetra-n-butyl titanate and chemical reaction between pimelic acid and calcium ion. X-ray diffraction and scanning electron micrograph confirmed the formation of TiO 2 on the surface of MMT. The differential scanning calorimeter and X-ray diffraction illustrated that the β-iPP composites filled by TiO 2 and MMT had lower relative β-phase contents than β-iPP. It is observed by polarized optical microscope that addition of TiO 2 -supported MMT with a β-nucleating surface into iPP can increase the spherulite nuclei density and decrease the spherulite size significantly and obtain the β-iPP/TiO 2 /MMT composites with high relative β-phase content.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 21
·3815
·
IF 4.329
Wanxin Peng,Furui Sun,Yuke Liang,Jian Kang,Jinyao Chen,Wei Wang,Ya Cao,Ming Xiang
In this study, one of the commonly used MXene (Ti3C2Tx) and β nucleated isotactic polypropylene (β-iPP)/MXene composites of different compositions were fabricated. The effects of MXene on non-isothermal crystallization and polymorphic behavior of β-iPP/MXene composites were comparatively studied. The non-isothermal crystallization kinetics indicates that for all samples, the lower cooling rates promote composites to crystallize at higher temperatures. When MXene and β-Nucleating agent (β-NA) are added separately, the crystallization temperature of composites shifts towards higher temperatures at all cooling rates. When MXene and β-NA are added simultaneously, the composite shows different cooling rate dependence, and the effects of improving crystallization temperatures is more obvious under rapid cooling. The activation energy of four samples iPP, iPP/MXene, iPP/β-NA, and iPP/MXene/β-NA were −167.5, −185.5, −233.8, and −218.1 kJ/mol respectively, which agree with the variation tendency of crystallization temperatures. The polymorphic behavior analysis obtained from Differential Scanning calorimetry (DSC) is affected by two factors: the ability to form β-crystals and the thermal stability of β-crystals. Because β-crystals tend to recrystallize to α-crystals below a critical temperature, to eliminate the effect of β-α recrystallization, the melting curves at end temperatures Tend= 50 °C and Tend= 100 °C are comparatively studied. The results show that more thermally unstable β-crystals would participate in β-α recrystallization with higher cooling rates. Moreover, thermal stability of β-crystals is improved by adding MXene. To further verify these findings, samples of three different thermal conditions were synthesized and analyzed by DSC, X-Ray Diffraction (XRD), and Polarized Light Optical Microscopy (PLOM), and the results were consistent with the above findings. New understandings of synthesizing β-iPP/MXene composites with adjustable morphologies and polymorphic behavior were proposed.Keywords:istotactic polypropylene;MXene;nonisothermal crystallization behavior
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2019
·
IF 3.714
Xiaoyu Meng,Chunhuan Liu,Chen Cao,Zhaojun Zheng,Qingfeng Su,Yuanfa Liu
L-ascorbyl palmitate (L-AP) is a potential fat crystallization modifier, formed by the ester bond of ascorbic acid and palmitic acid. The effects of L-AP on the crystallization behavior of palm oil (PO) and its application in bread were systematically investigated. L-AP addition led to higher crystallization rate and lower induction time of nucleation with the increasing concentration from 1% to 5%. L-AP slightly affected the growth mechanism of PO, and they all showed the instantaneous nucleation and linear growth. Meanwhile, in presence of L-AP, a desirable β′ polymorphism and lower thickness of the nanoscale crystals were observed in the PO. Higher fractal dimension (D b ) and smaller average particle size (D) were acquired by analyzing the polarized light microscope (PLM) pictures, which represented more ordered organization of the crystal lattice due to the interactions between triglycerides and L-AP. Furthermore, the specific volume increased and the baking decreased after adding L-AP according to the baking analysis. Bread made of PO with L-AP was satisfactory, showing higher cell density, smaller cell average area and lower hardness. In summary, L-AP had great potential to be a highly effective fat crystallization modifier and increased the compatibility of PO to be severed as the formulations of baking fat in the food industry.
研究领域:
食品科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）