Polish Journal of Chemical Technology
·
2020
·Vol. 22
·期 4
·61-68
·
IF 1.193
Xiaonan Deng,Sihong Ye,Kun Liu,Changfeng Li,Fangzhi Liu,Xiaoming Yan
To collect permeability data and establish its database of fertilizer nutrients and water vapor through different polymer membranes for the development of polymer-coated fertilizer, the permeabilities of N-, P-, and K-nutrient from saturated aqueous of urea, NaH2PO4 and KCl solution and the permeability of water vapor through the membranes of poly lactic acid (PLA), its blends with polystyrene (PS), and its composites with humic acid (HA) particles were determined experimentally at the temperatures of 288, 298, and 308 K, respectively. The effects of the addition of PS and HA particles, temperature, and coating thickness on the permeability of fertilizer nutrient and water vapor were investigated. It was found that the addition of PS and HA increased the permeability for both the fertilizer nutrients and water vapor. The increase in temperature raised the permeability of N-, P-, and K-nutrient while decrease the permeability of water vapor in the range studied.
研究领域:
农业科学
·
材料科学
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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
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材料科学
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产品关联
DOI
高影响因子
MACROMOLECULES
·
2013
·
IF 5.521
Jun Shao,Jingru Sun,Xinchao Bian,Yi Cui,Yunchun Zhou,Gao Li,Xuesi Chen
The crystallization and melting behaviors of polylactide (PLA) homochiral polymer under the confinement of stereocomplex crystallites were studied in the linear and three-armed poly(d-lactide)/poly(l-lactide) (PDLA/PLLA and 3PDLA/3PLLA) solution casting blends. WAXD results showed that novel modified crystallites formed when PLA homopolymer crystallized from the melting state. And the modified crystallites formed in 3PDLA/3PLLA blends (M-A) were less stable than that formed in similar PDLA/PLLA blends (M-B) after specimens cooled at a specific rate. Although these modified crystallites differed from PLA α crystallites (M-C), both of them transformed into α crystallites during heating. The transitions among different crystallites revealed the multiple melting behaviors in DSC measurement. The type of PLA homochiral crystallites and their contents mainly depended on the D/L compositions, annealing conditions, molecular weights, and architectures of the polymers in the blends. The formation of these modified crystallites should be ascribed to the confinement of PLA stereocomplex and steric hindrance of polymers, and PLA homopolymer could not charge into lattice orderly during rapid crystallization.
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DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 56
·50543-50552
·
IF 3.289
Weiwei Zhang,Delong Zhang,Xiaoshan Fan,Guangyue Bai,Yuqin Jiang,Zhiguo Hu
Novel dumbbell-shaped amphiphilic copolymers ((PLLA)2–G1–P188–G1–(PLLA)2 and (PDLA)2–G1–P188–G1–(PDLA)2) and linear-shaped amphiphilic copolymers (PLLA–P188–PLLA and PDLA–P188–PDLA) were synthesized by click chemistry and ring opening polymerization (ROP). The stereocomplexes (scPLA)2–G1–P188–G1–(scPLA)2 and scPLA–P188–scPLA were prepared and confirmed by X-ray diffraction (XRD). The stereocomplex interaction between PLLA and PDLA was firstly analyzed using microscale thermophoresis (MST) technology and the dissociation constant (Kd) was obtained as 342 μM. The aggregation behaviors of these stereocomplexes were studied using fluorescence spectroscopy, transmission electron microscopy (TEM) and light scattering (LS). The critical aggregate concentration (CAC) obtained from fluorescence measurements was 0.021 mg mL−1 for (scPLA)2–G1–P188–G1–(scPLA)2 and 0.042 mg mL−1 for scPLA–P188–scPLA. These stereocomplexes can self-associate in aqueous solution into spherical aggregates with a diameter of 181 nm for (scPLA)2–G1–P188–G1–(scPLA)2 and 222 nm for scPLA–P188–scPLA. Furthermore, the biocompatibility of the stereocomplexes was evaluated with a relatively lower cytotoxicity. Finally, DOX was encapsulated into the stereocomplex aggregates to evaluate the drug release ability in phosphate buffer at a pH value of 7.4 or 5.4. The drug loading content and the encapsulation efficiency of the aggregates are 9.8%, 54% for (scPLA)2–G1–P188–G1–(scPLA)2 and 8.2%, 45% for scPLA–P188–scPLA. The release of DOX at pH 5.4 is faster than that at pH 7.4. The pH value has a greater effect on the release rate of DOX from dumbbell-shaped stereocomplex aggregates than that from the linear-shaped ones, which ensures the long blood circulation and the higher DOX-release surrounding the tumor site.
研究领域:
材料科学
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生物医学工程
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药剂学
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产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 6
·1579
·
IF 5
Deling Li,Congcong Luo,Jun Zhou,Liming Dong,Ying Chen,Guangtian Liu,Shuyun Qiao
Corn starch was plasticized by glycerol suspension in a twin-screw extruder, in which the glycerol suspension was the pre-dispersion mixture of glycerol with nano-SiO2. Polylactide (PLA)/thermoplastic starch/SiO2composites were obtained through melt-blending of PLA with thermoplastic starch/SiO2in a twin-screw extruder. The nonisothermal crystallization behavior of PLA in the composites was investigated by differential scanning calorimetry. An interface of PLA with thermoplastic starch was proven to exist in the composites, and its interfacial bonding characteristics were analyzed. The interfacial binding energy stemming from PLA with thermoplastic starch exerts a significant influence on the segmental mobility of PLA at the interface. The segmental mobility of PLA is gradually improved by increasing interfacial binding energy, and consequently, the relative crystallinity on the interface exhibits progressive promotion. The Jeziorny model could well describe the primary crystallization of PLA in the composites. The extracted Avrami exponents based on the Jeziorny model indicate that the primary crystallization of PLA follows heterogeneous nucleation and three-dimensional growth. This study has revealed the intrinsic effect of the interfacial segmental mobility on the nonisothermal crystallization behavior of PLA in composites, which is of technological significance for its blow molding.Keywords:polylactide;composites;interfacial binding energy;nonisothermal crystallization kinetics
研究领域:
材料科学
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高分子科学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 7
·1197
·
IF 3.164
Wei Li,Jie Wu,Xingui Cheng,Lanjuan Wu,Zhi Liu,Qingqing Ni,Yuhao Lu
The impact of hydroxypropylsulfonation/caproylation on the adhesion of cornstarch to polylactic acid (PLA) fibers was investigated for ameliorating the applications such as PLA sizing. The hydroxypropylsulfonated and caproylated cornstarch (HCS) samples with different degrees of substitution (DS) were synthesized by a hydroxypropylsulfonation of acid-converted cornstarch (ACS) with 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) and subsequently a caproylation with caproic anhydride (CA). The HCS granules were characterized by Fourier transform infrared spectroscopic and scanning electron microscopy. The adhesion was evaluated by measuring the bonding forces of the PLA roving impregnated. The mechanical behaviors of the adhesive layers were estimated by determining the properties of the films. The results of adhesion measurement were also analyzed especially through the wetting and spreading of the paste on the fiber surfaces, as well as the failure type, internal stress and mechanical behaviors of the adhesive layers among fibers. Additionally, apparent viscosity and its stability of the pastes were also determined. It was found that hydroxypropylsulfonation/caproylation was not only able to obviously improve the adhesion of ACS to PLA fibers, but also capable of further improving the adhesion of hydroxypropylsulfonated starch (HS) to the fibers. With the rise in the total DS, the adhesion gradually increased. The two substituents improved the wetting and spreading, reduced the internal stress, lowered the probabilities of interfacial failure and cohesive failure, decreased the film brittleness, and increased the van der Waals force at the interfaces. Moreover, the HCS samples with a stability of above 85% could meet the demand on the stability for sizing. Considering the experimental results of the adhesion and the analysis of the results, HCS showed potential in the application of PLA sizing.Keywords:hydroxypropylsulfonation/caproylation;cornstarch;past stability;adhesion;PLA fibers;film properties
研究领域:
材料科学
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高分子化学
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产品关联
DOI
PubMed
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2017
·
IF 4.873
Shaoping Qian,Kuichuan Sheng
To toughen brittle poly(lactic acid) (PLA) composites, surface-modified bamboo cellulose nanowhiskers (BCNW) were introduced into a PLA matrix. The BCNW was treated with (3-mercaptopropyl)trimethoxysilane (A-189) at five concentrations between 1 wt% to 16 wt% to improve compatibility. Silylated BCNW-toughened PLA composite films were further fabricated by solution casting . The coupled reaction between A-189 and cellulose via Si-O-C bonding and hydrogen bonding was confirmed. BCNW was silylated uniformly and maintained its original morphology. With increasing concentration, BCNW became smooth; however, with excessive coupling agent, the BCNW surface became rough. Elongation at break was inversely proportional to tensile strength and tensile modulus . Elongation at break increased to 250.8% after the 4 wt% A-189 treatment compared to 12.35% with untreated composites. The C/O ratio of BCNW decreased after coupling agent treatment. There were physical interlocks and hydrogen bonding between two phases. A wire-drawing phenomenon was observed on the tensile fractural surface. The thermal degradation stability decreased with the increasing treatment concentration.
研究领域:
材料科学
·
生物复合材料
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产品关联
DOI
高影响因子
Polymer Chemistry
·
2023
·
IF 4.6
Tong Zhou,Yu-Ting Guo,Chun Yang,Xian-Bin Meng,Fusheng Du,Zichen Li
A new bicyclic lactone, 2,5,7-trioxabicyclo[2.2.2]octan-6-one (TOB), was synthesized by direct condensation reaction of glycerol and glyoxylic acid. The ring-opening polymerization (ROP) of TOB and its copolymerization with lactide (LA) under different conditions were systematically investigated. Both acid and base could catalyze the ROP of TOB, but only oligomers were obtained in low yields. Three discrete oligomers (O1, O2, and O3) of TOB were separated and characterized, confirming that the high crystallinity and poor solubility of PTOB in the polymerization media caused the low monomer conversion and low molar mass of PTOB. Copolymerization of LA and TOB was investigated with benzyl alcohol as the initiator and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst. It was confirmed that LA was consumed very quickly to form PLA, followed by slow incorporation of TOB into the formed PLA chains. By varying the feed ratios of LA to TOB, a series of random copolymers with the incorporation ratio of TOB up to 49 mol% were obtained. These copolymers exhibited high glass transition temperatures (Tg) up to 100 oC. The TBD-catalyzed copolymerization mechanism was revealed to be a base-catalyzed transesterification of PLA and TOB. Finally, PLA-co-PTOB with variable Tg could thus be simply prepared by direct transesterification of PLA with TOB in the presence of TBD.
研究领域:
材料科学
·
高分子化学
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2026
·
IF 3.9
Xiaoxi Huang,Yuan Sang,Hailing Liu,Yifeng Sun
Mechanochemistry is an efficient, solvent-reduced, and extra heat-free green chemistry method. In this work, mechanochemistry is applied to the polymerization of PLA. The resulting PLA was esterified with citric acid to obtain a vitrimer-like polymer, which was also carried out via mechanochemistry. These mechanochemistry processes were performed using a planetary ball mill, which is favorable for scale-up synthesis. The synthesized polymer was characterized by NMR and SEC, and the vitrimer-like properties were evaluated by rheology, DSC, TGA, and shape memory behavior. Graphical Using mechanochemistry, PLA is polymerized via an efficient, solvent-reduced, heat-free route. The as-synthesized PLA is then further converted into a vitrimer-like polymer by mechanochemical modification. The resulting material exhibits dynamic network behavior, as confirmed by thermal, rheological, and shape-memory analyses.
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2026
·
IF 8.7
Ziyang Zhang,Xue Xu,Shangming Xia,Feng-lei Zhou,Yanfen Zhou,Liang Jiang,Shaojuan Chen
Polylactic acid (PLA) fibers hold great promise in biomedicine and functional textiles, yet their inherent brittleness and lack of antibacterial properties limit widespread use. Conventional modifications often suffer from poor interfacial compatibility or potential cytotoxicity. Herein, we developed tough, antibacterial PLA composite fibers via scalable melt-spinning, using a rationally designed PLA-based polyurethane (PLA-PU) block copolymer as an interfacial compatibilizer and toughening agent, followed by surface immobilization of the natural antimicrobial peptide ε-polylysine (ε-PL). Intermolecular hydrogen bonding and identical PLA chain segments induce a favorable micro-phase separation, which acts as an effective stress concentrator to trigger massive shear yielding, significantly improving elongation at break while maintaining a robust tensile strength (73 MPa) suitable for medical textiles. The resulting topological roughness and micro-voids, combined with electrostatic interactions, provide robust physical anchoring sites for ε-PL, endowing the fibers with high antibacterial activity (>95% against E. coli and S. aureus ) and acceptable washing durability. This study elucidates the structure–property relationships in micro-phase separated biopolymer blends, offering a facile, eco-friendly, and biosafe strategy for engineering multifunctional PLA fibers for advanced biomedical applications.
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DOI
PubMed
高影响因子
Polymers
·
2022
·Vol. 14
·期 8
·1530
·
IF 4.967
Hui Fang,Lingjie Zhang,Anlin Chen,Fangjuan Wu
Polylactic acid (PLA)-thermoplastic polyurethane (TPU) copolymer (PTC) was prepared by melting TPU pellets in molten lactide, followed by in situ ring-opening coordination polymerization. The results from FTIR and1H-NMR confirmed the formation of the copolymer. PLA/TPU blends with different TPU contents were prepared by melt blending method. SEM and mechanical properties showed a conspicuous phase separation between PLA and TPU. In order to further improve the mechanical properties of the blend, PTC was used as the compatibilizer and the effects of the PTC content on the properties of the blend were investigated. The addition of PTC made TPU particles smaller in PLA matrix and improved the compatibility. With the loading of 5 wt.% PTC, the impact strength of the PLA/TPU blend reached 27.8 kJ/m2, which was 31.1% and 68.5% higher than that of the blend without PTC and pure PLA, respectively. As the content of PTC was more than 5 wt.%, the mechanical properties declined since the compatibilizer tended to form separate clusters, which could reduce the part distributed between the dispersed phase and the matrix, leading to a reduction in the compatibility of the blend. Moreover, the DMA results confirmed PTC could improve the compatibility between PLA and TPU.Keywords:polylactic acid;thermoplastic polyurethane;in situ polymerization;compatibility
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
PubMed
高影响因子
MARINE POLLUTION BULLETIN
·
2023
·
IF 5.8
Minggu Zhang,Na Liu,Lei Hou,Chao Li,Chengliang Li
Both non-degradable and biodegradable plastics can act as vectors of diverse organic pollutants. In this study, two types of biodegradable microplastics [poly (butylene adipate- co -terephthalate) (PBAT) and polylactic acid (PLA)] and one type of non-degradable microplastics [polypropylene (PP)] were selected to investigate the impacts of ultraviolet (UV) irradiation for one month on microplastics surface modification and their adsorption behaviors for chlorpyrifos (CPF). The study revealed that PBAT held the largest adsorption capacity, and PLA held the fastest adsorption rate. The UV irradiation diminished the adsorption capacities on PLA and PP but enhanced the adsorption capacities on PBAT. The adsorption capacity normalized by specific surface area revealed that specific surface area was the dominant factor for affecting the adsorption capacities on PP and PLA after UV irradiation. These findings further clarify the interaction between CPF and microplastics, and provide a theoretical basis for assessing the ecological risk of microplastics in water.
研究领域:
环境科学
·
生态学
·
污染研究
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）