Polymers
·
2023
·Vol. 15
·期 2
·413
·
IF 5
Jialin Xu,Kuo Zhou,Linlin Qin,Zaiming Tan,Shijing Huang,Peigao Duan,Shimin Kang
The chemical recycling of end-of-life polylactic acid (PLA) plays roles in mitigating environmental pressure and developing circular economy. In this regard, one-pot tandem alcoholysis and hydrogenation of PLA was carried out to produce 1,2-propanediol, which is a bulk chemical in polymer chemistry. In more detail, the commercially available Raney Co was employed as the catalyst, and transformation was conducted in ethanol, which acted as nucleophilic reagent and solvent. Single-factor analysis and Box–Behnken design were used to optimize the reaction conditions. Under the optimized condition, three kinds of PLA materials were subjected to degradation. Additionally, 74.8 ± 5.5%, 76.5 ± 6.2%, and 71.4 ± 5.7% of 1,2-propanediol was yielded from PLA powder, particle, and straws, respectively, which provided a recycle protocol to convert polylactic acid waste into value-added chemicals.Keywords:polylactic acid;alcoholysis;hydrogenation;1,2-propanediol;PLA straws
研究领域:
化学工程
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环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Applied Biomaterials & Functional Materials
·
2016
·
IF 0.934
Junyan Yao,Shijie Zhang,Wudan Li,Yujie Li
BackgroundThe amorphous poly(lactic acid-co-lysine) (PLL) with hydrophilic reactive groups was synthesized by the condensing copolymerization and the blending miscibility of poly(L-lactic acid) (PLLA) and PLL was investigated.MethodsThe miscibility of PLLA and PLL was evaluated by analyzing the thermal properties, crystallization behaviors, crystal morphologies and mechanical properties of the PLLA/PLL blends.ResultsThe results indicated that amorphous PLL changed the crystallization behaviors and thermal properties of PLLA, decreasing the crystallinity of PLLA in the blends. The amorphous PLL molecule chains in PLLA/PLL blends were able to enter into the lamellars of PLLA spherulites and affect the crystallization behaviors of PLLA, resulting in imperfect, spherulite structures of PLLA. The formation of hydrogen bonds between PLLA molecular chains and PLL molecular chains enabled partial compatibility in this blend system.ConclusionsThe existence of PLL improved the hydrophility of PLLA/PLL blends, led to a higher content of PLL in the PLLA/PLL blend system, and better hydrophilic properties of the blend system. The PLL was partially miscible with the PLLA, and the PLLA/PLL blend with 10 wt% PLL had improved tensile properties.
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
RSC Advances
·
2015
·Vol. 5
·期 95
·78306-78314
·
IF 3.84
Xuemin Yu,Fu Liu,Linghui Wang,Zhu Xiong,Yunze Wang
Poly(lactic acid) (PLA) is a sustainable membrane candidate for liquid separation and purification. However, the inherent brittleness restrains its practical application, especially for a porous membrane with thin thickness and high porosity. We aim to prepare PLA membranes with controlled pore structure and dialysis performance with improved mechanical and thermal stability by incorporating polysulfone-graft-poly(lactic acid) (PSf-g-PLA) copolymer. Different from the common rubbery elastomer, the brush-like PSf-g-PLA copolymer with a rigid backbone chain and soft side chains was elaborately synthesized to toughen and modify PLA membranes via a phase inversion process. 1H NMR, FTIR and GPC were conducted to determine the structure and molecular weight of the PSf-g-PLA. The influences of chloromethylation substitution and the content of copolymer on the membrane microstructure, the mechanical and thermal stability, and the dialysis performance were investigated in detail. It was demonstrated that the modified PLA membrane exhibited a pure water flux of 54 L m−2 h−1, 95% rejection to BSA, and 65% and 18% clearance of urea and lysozyme, respectively. Besides, both mechanical and thermal stability of the modified PLA membrane were improved by incorporating brush-like PSf-g-PLA.
研究领域:
材料科学
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·Vol. 142
·期 14
·e56682
·
IF 2.8
Huili Liu,Luyao Su,Ruihan Li,Liting Wang,Dongyu Bai
In this article, poly(ethylene glycol)-poly( d -lactide) (PEG-PDLA) block copolymers with different PEG chain lengths were synthesized and melt-mixed with poly( l -lactide) (PLLA) and rubber nanoparticles. The role of PEG-PDLA block copolymers in tailoring the microstructures and performances of PLLA/rubber blend were investigated in detail. It was found that high contents of stereocomplex (SC) crystals were generated in PLLA/rubber/PEG-PDLA copolymer blends, which induced rubber nanoparticles to agglomerate and form network-like structures. The size of rubber aggregates and continuity of rubber network-like structures first increased and then declined significantly as the PEG chain length increased. Resultingly, the impact toughness of PLLA/rubber/PEG-PDLA copolymer blends first remarkably increased to 74.1 kJ/m 2 and then decreased to 30.6 kJ/m 2 . Meanwhile, the elongation at break increased with increasing PEG chain length and little loss of tensile strength happened, revealing good stiffness-toughness balance performances of PLLA/rubber/PEG-PDLA copolymer blends. Moreover, the matrix crystallization rate of PLLA/rubber/PEG-PDLA copolymer blends could be greatly increased by increasing PEG chain length and the PLLA/rubber/PEG-PDLA copolymer blends exhibited much higher Vicat softening temperatures than PLLA/rubber blend, which confirmed the excellent heat resistance of PLLA/rubber/PEG-PDLA copolymer blends. These interesting findings suggested that PEG-PDLA block copolymers were highly conducive to prepare PLLA materials with outstanding comprehensive performances.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS & POLYMER COMPOSITES
·
2019
·
IF 0.683
Yongji Gong,Weihua Song,Yifan Wu,Daohai Zhang,Yufei Liu,Qian Zhao,Min He,Xiaolang Chen
The poly(l-lactide-b-ethylene glycol-b-l-lactide) (PLLA-PEG-PLLA) triblock copolymers with different chain segment length are fabricated by ring-opening polymerization. The structure, molecular weight, and crystallization behaviors of the triblock copolymers are characterized by Fourier transform infrared, nuclear magnetic resonance spectroscopy, gel permeation in chromatography, X-ray diffraction, differential scanning calorimetry, and polarizing optical microscopy (POM). The results show that the increase of block length is beneficial to improve its crystallization. In addition, the triblock copolymer exhibits a double crystallization phenomenon. The POM results indicate that PEG and PLLA chains of the copolymer crystallize in their respective crystallization temperature regions. The growth rate of the PLLA spherocrystal decreases and the dendritic spherocrystals appear with increasing the PEG chain length when the PLLA chain of the copolymer is isothermal crystallized at 80°C and PLLA chain length is constant. The growth rate of the PEG spherocrystal decreases and the spherocrystal morphology changes little with increasing PLLA chain length when the PEG chain is isothermal crystallized at 25°C and the length of PEG chain remained unchanged.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2015
·
IF 3.163
Lidong Feng,Xinchao Bian,Gao Li,Zhiming Chen,Xuesi Chen
A series of novel biodegradable polyurethanes (PELU) based on poly(ethylene glycol)- b -polylactide copolymers were prepared by chain extension with isophorone diisocyanate (IPDI). The PELUs were used to toughen polylactide (PLA) by melt blending. The results of DSC and SEM uniformly indicated that the PELUs were partially compatible with PLA and the PLA segments in PELU could effectively improve the compatibility between PLA and PELU. PELU as a plasticizer could significantly improve the toughness of PLA materials and remain their high strength and modulus. When the PELU content was 10–20 wt%, the elongation at break of PLA/PELU-40/ADR (0.4 wt%) and PLA/PELU-50/ADR (0.4 wt%) reached up to 250%–350%. When the PELU content was 20 wt%, the tensile strength and modulus of PLA blends containing PELU-30, PELU-40 and PELU-50 maintained 35–38 MPa and 1300–1500 MPa, respectively. The moisture absorption of the PLA materials enhanced because of blending with PELU containing PEG segments, but the hydrolytic degradation property of PLA materials was little affected by this.
研究领域:
材料科学
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2013
·Vol. 3
·期 40
·18464-18473
·
IF 2.562
Jian Zhou,Zhiqiang Jiang,Zongbao Wang,Jianqiang Zhang,Jun Li,Ya Li,Junwu Zhang,Peng Chen,Qun Gu
A series of poly(L-lactide)-b-poly(butylene terephthalate)- b-poly(L-lactide) (PLA-b-PBT-b-PLA) triblock copolymers were synthesized via ring-opening polymerization of L-lactide with hydroxyl-functionalized poly(butylene terephthalate) (HOPBT) as macroinitiator and stanneous 2-ethylhexanoate (Sn(Oct)2) as the catalyst in 1,1,2,2-tetrachloroethane (TCE). The conversion of L-lactide was high and the PLA block in the copolymers showed high optical purity. Chemical structure and physical properties of the triblock copolymers were studied using NMR, GPC, DSC, and WAXD. The block structure of the copolymers was confirmed using NMR, and each block formed the same crystal type as the respective homopolymer, i.e., PLA or PBT as revealed by DSC and WAXD. The copolymer, even at a very low content (5 wt%), showed an unexpected favoring effect on the crystallization of PLA, which made it a potential polymeric nucleating agent for PLA.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·
IF 2.7
Liqing Li,Xiumin Zhong,Minghao Zheng,Panwang Wu,Fei Yu,Shaobo Ouyang,Jie Ma
As emerging pollutants, microplastics have attracted significant attention in recent years. To evaluate the potential carrier effect of degradable microplastics on coexisting contaminants, we used UV light at different wavelengths, 254 nm and 340 nm, to simulate laboratory-accelerated aging and natural noon direct solar aging, respectively. A study was carried out to analyze the adsorption and desorption properties of polylactic acid (PLA) on bisphenol A (BPA) before and after aging. Compared to the UV-340 nm aged PLA (Aged-PLA 2), the UV-254 nm aged PLA (Aged-PLA 1) showed a significant yellowing phenomenon, the original larger PLA particles cracked into smaller ones, and more pronounced changes were observed in surface functional groups and physicochemical properties. The zeta potential of Aged-PLA 1 exhibited a decrease from −24.75 mV to −30.35 mV. By contrast, there was no fixed trend in the Zeta potential changes of Aged-PLA 2. In adsorption experiments, the original PLA and Aged-PLA 2 showed similar adsorption capabilities for BPA, which were higher than those of Aged-PLA 1. Desorption experiments showed that aged PLA desorbed from BPA to an extent greater than that of the original PLA, indicating that the aged PLA had a greater capacity for the pollutant to migrate. The desorption of BPA was found to be higher in simulated intestinal fluid than in ultrapure water, suggesting that PLA adsorbed on BPA faces a higher ecotoxicological risk in organisms. Overall, these results will contribute to the comprehension of the carrier effect and potential ecological risk of MPs on coexisting pollutants.
研究领域:
环境科学
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生态学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2017
·Vol. 9
·期 8
·323
·
IF 3.364
Xin-yu Song,Meng Wang,Yun-xuan Weng,Zhi-gang Huang
Bamboo flour (BF) was grafted onto lactide (LA) in the molten state using stannous octoate as a catalyst to form BF-g-LA. Then, polylactic acid (PLA) was blended with BF (PLA/BF, 85/15 wt %) to prepare PLA/BF/BF-g-LA composites using BF-g-LA as a compatibilizer. The grafting rate of BF was characterized using infrared testing and elemental analysis. To investigate the effect of BF-g-LA on the performance of PLA/BF/BF-g-LA composites, the phase morphology, thermal stability, and mechanical properties of the composites were characterized using scanning electron microscopy, thermogravimetric analysis, and universal material testing, respectively. The addition of BF-g-LA improved the interface compatibility between PLA and BF. When the BF-g-LA content was 2 phr, the tensile and impact strengths of PLA/BF/BF-g-LA composites were 55.3 MPa and 9.56 kJ/m2, representing 30% and 27% increases, respectively, relative to corresponding values for PLA/BF composites.Keywords:bamboo flour;lactide;graft;polylactic acid;compatibility
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 9
·5645-5657
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IF 4.682
Ma Meng,Wang Xinpeng,Liu Kai,Chen Si,Shi Yanqin,He Huiwen,Wang Xu
Preparing poly(lactic acid) (PLA) composites with toughness and flame retardancy simultaneously is a challenge that many researchers faced. In this paper, flame-retardant and toughened PLA composites were prepared by reactive blending with in-situ formed polyurethane as the toughening phase and ammonium polyphosphate (APP) as the flame retardant. By adding glycerin as a cross-linking agent, the dropping behavior of the composites during combustion is reduced, and the toughness is greatly improved. Compared with the blended composites without the cross-linking agent, the tensile strengths of the composites with the cross-linking degree of 10% are increased by 16%, and the impact strength is increased by 11 times. The composites with 5% APP and 10% cross-linking degree had balanced performance, the vertical combustion can reach V-2 level, and the elongation at break is about 200%. The research provides a simple method to fabricate flame retardant and degradable PLA-based composites with simultaneously enhanced mechanical properties. Graphical abstract
Compared with linear polyurethane, the PLA composite material toughened by cross-linked polyurethane not only had a higher elongation at break but also decreased the droplet during the combustion process.
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
MOLECULES
·
2022
·Vol. 27
·期 15
·4748
·
IF 4.927
Qing Zhang,Huiyuan Liu,Junxia Guan,Xiaochun Yang,Baojing Luo
Phosphating sesbania gum (DESG) was obtained by modifying sesbania gum (SG) with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and endic anhydride (EA). The structure of DESG was determined using Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H-NMR). Flame-retardant polylactic acid (PLA) composites were prepared by melt-blending PLA with DESG, which acted as a carbon source, and ammonium polyphosphate (APP), which acted as an acid source and a gas source. The flame retardancy of the PLA composite was investigated using vertical combustion (UL-94), the limiting oxygen index (LOI) and the cone calorimeter (CONE) test. Thermal properties and morphology were characterized via thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM), respectively. Experimental results indicated that when the mass ratio of DESG/APP was equal to 12/8 the LOI value was 32.2%; a vertical burning test (UL-94) V-0 rating was achieved. Meanwhile, the sample showed a lowest total heat release (THR) value of 52.7 MJ/m2, which is a 32.5% reduction compared to that of neat PLA. Using FESEM, the uniform distribution of DESG and APP in the PLA matrix was observed. The synergistic effect of DESG and APP effectively enhanced the flame retardancy of PLA. Additionally, the synergistic mechanism of DESG and APP in PLA was proposed.Keywords:polylactic acid;sesbania gum;ammonium polyphosphate;flame retardancy
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Sustainability
·
2022
·Vol. 14
·期 19
·12872
·
IF 3.889
Zihan Lang,Lidong Xue
Triclosan (TCS) has been widely employed as active ingredient in household products and has received attention for its hepatotoxicity, endocrine disruption and disturbance on immune function. Polylactic acid (PLA) has been highlighted as an alternative biodegradable microplastic, and the knowledge about the adsorption affinity towards TCS is limited. In this study, the ability to act as carrier of TCS by PLA and non-biodegradable microplastics, including polystyrene (PS), polyvinyl chloride (PVC) and polyethylene (PE) with different particle sizes were explored. The influence factors (e.g., dosage, pH and salinity), adsorption kinetics and isotherms were also investigated. Batch experiment results indicated that the TCS adsorption onto PLA and non-biodegradable microplastics exhibited a pronounced pH-dependent pattern (pH of 4, 7 and 10), and the adsorption capacity decreased gradually as pH increased. Furthermore, the adsorption capacity of TCS on PS, PVC and PE decreased as salinity increased from 0 to 3.5%, while no significant inhibition for the sorption capacity of PLA was observed. The adsorption kinetic data of TCS was best fitted with the pseudo-second order model. The Freundlich model with R2(0.999) was suitable to describe the adsorption isotherms of TCS on PLA, while the isotherms data of TCS on PS, PVC and PE was fitted by linear and Freundlich model. The higher adsorption capacity of PLA (38.6 mg g−1) compares to those of PS, PVC and PE (31.3, 11.4 and 9.64 mg g−1, respectively), illustrated by the fact that the physicochemical properties of microplastics have a noticeable impact on adsorption process, and the biodegradable PLA is a stronger vector than the non-biodegradable microplastics.Keywords:triclosan;polylactic acid;vector;pH-dependent
研究领域:
环境科学
·
材料科学
✓ 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）