CRYSTENGCOMM
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2015
·Vol. 18
·期 2
·274-282
·
IF 4.034
Jun Shao,Yanmei Guo,Sheng Xiang,Dongdong Zhou,Xinchao Bian,Jingru Sun,Gao Li,Haoqing Hou
Linear and three-armed poly(L-lactide)/poly(D-lactide) (PLLA/PDLA, 3PLLA/3PDLA and 3PLLA/PDLA) specimens were prepared through a solution mixing method, and the morphology and the spherulite growth of poly(lactide) stereocomplex crystallites (PLA sc) from the melt with various structures and molecular weights were investigated. Polarized optical microscopy images revealed that regular spherulites and a visible boundary developed in all of the PLLA/PDLA blends with relatively lower molecular weights (Mn < 20 kg mol−1 for each branch), and irregular spherulites formed when the molecular weights of PLA polymers were higher than 60 kg mol−1. The growth rate of the spherulites (G) increased at first, and then decreased as the molecular weight increased in all of the PLLA/PDLA, 3PLLA/3PDLA and 3PLLA/PDLA specimens. The highest G value in all of the specimens was achieved when the average molecular weights of each branch were ∼10 kg mol−1. With similar molecular weights for each of the branches, the G reduced gradually as the three-armed PLA was added to the blend (i.e., PLLA/PDLA > 3PLLA/PDLA > 3PLLA/3PDLA).
研究领域:
材料科学
·
高分子化学
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Wen Zhang,Hongming Liu,Li Yan,Xi Mei,Zikang Hou
Developing of the multifunctional polymeric carrier for controlled drug release is still one of most challenging task. In this work, a pH-responsive dual drug delivery system was designed and prepared based on the zeolitic imidazolate framework-8 (ZIF-8). The poly(lactic acid)/chitosan (PLA/CS) core-shell nanofiber membranes by emulsion electrospinning, which the hydrophilic drug (Astragalus Polysacharin, APS) was encapsulated in the CS core and the hydrophobic drug (Camptothecin, CPT) was loaded into the PLA shell, respectively. Subsequently, ZIF-8 nanoparticles served as the protective layer were immobilized on the surface of PLA/CS to form multi-structural PLA/CS@ZIF-8 nanofiber membranes. In vitro drug release of nanofiber membranes were studied in the acidic and neutral medium, respectively. The results were that the hydrophilicity and surface roughness of nanofiber membranes rose with increasing of 2-MIM concentrations. The nanofiber membranes also had excellent pH-responsive and controlled release property. Furthermore, the drug release of PLA/CS@ZIF-8 for either APS or CPT were all carried out in a coexisting manner of diffusion and skeleton corrosion. In addition, in vitro cytotoxicity assay indicated nanofiber membranes with good cytocompatibility. Therefore, the multi-structured PLA/CS@ZIF-8 nanofiber membranes has been used as a potential pH-responsive dual drug release system.
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PubMed
高影响因子
Polymers
·
2022
·Vol. 14
·期 12
·2317
·
IF 4.967
Juliene Oliveira Campos de França,Deborah da Silva Valadares,Mateus Freitas Paiva,Sílvia Cláudia Loureiro Dias,José Alves Dias
Poly(lactic acid) (PLA) is an important polymer that is based on renewable biomass resources. Because of environmental issues, more renewable sources for polymers synthesis have been sought for industrial purposes. In this sense, cheaper monomers should be used to facilitate better utilization of less valuable chemicals and therefore granting more sustainable processes. Some points are raised about the need to study the total degradability of any PLA, which may require specific composting conditions (e.g., temperature, type of microorganism, adequate humidity and aerobic environment). Polymerization processes to produce PLA are presented with an emphasis on D,L-lactic acid (or rac-lactide) as the reactant monomer. The syntheses involving homogeneous and heterogeneous catalytic processes to produce poly(D,L-Lactic acid) (PDLLA) are also addressed. Additionally, the production of blends, copolymers, and composites with PDLLA are also presented exemplifying different preparation methods. Some general applications of these materials mostly dedicated to the biomedical area over the last 10–15 years will be pointed out.Keywords:poly(lactic acid)-PLA;polymerization based on D,L-lactic acid;D,L-lactide;stereo polymerization of D,L-lactic acid;blends of PLA;poly(DL-lactide-co-polymer);composites of PDLLA
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高影响因子
IONICS
·
2017
·Vol. 24
·期 3
·787-795
·
IF 2.062
Wang Ping,Zhang Di,Zhou Yiyang,Li Yu,Fang Huagao,Wei Haibing,Ding Yunsheng
A novel biodegradable 1,2,3-triazolium-functionalized PEG- b -PCL copolymer (TAPEC) was synthesized by the “click” coupling of methoxypolyethylene glycol azide and α-propargyl-ω-hydroxyl-poly(ε-caprolactone), followed by the quaternization of the 1,2,3-triazole moiety with iodomethane. All the intermediates and TAPEC were characterized by 1 H NMR, FT-IR, and gel permeation chromatography (GPC). Taking advantage of the characteristics of ionic liquid and block copolymer, this ion-containing diblock copolymer is expected to be used as a novel compatibilizer in mixed biopolyester for regulating the interface and crystallization behaviors. Hence, the TAPEC was evaluated as a compatibilizer and an interface emulsifier in the blends of polylactic acid (PLA) and poly(ε-caprolactone) (PCL). Non-isothermal crystallization experimental results showed that the TAPEC with the higher amount of ε-caprolactone units induces a plasticization and nucleate effect that increased the crystallization ability of the PLA phase; meanwhile, in the PCL phase, the agminated ionic cluster acting as a nucleating agent significantly increased the crystalline of PCL.
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CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Yu Huang,Guoping Zhu,Zhennan Wang,Yadong Wang,Zongmin Zhu
This study designed and synthesized a novel phosphorus silicon synergistic flame retardant PDD. Only adding 1 wt% PDD can achieve excellent UL-94 V-0 flame-retardant rating for PLA composite, and the limit oxygen index (LOI) can be increased to 26.8 %. At the same time, the thermal stability and crystallinity of composites are significantly improved. The results of the cone calorimeter test show that compared with pure PLA, PLA/1 % PDD reduces the peak heat release rate (pHRR), total heat release (THR), and peak of CO 2 release rate (pCO 2 P) by 38.2 %, 42.9 %, and 26.6 %, respectively. It is worth noting that PDD not only enhances the tensile strength and impact toughness of PLA composites, but also accelerates their chemical degradation process in alkaline environments through ester bond hydrolysis promoted by phosphorus silicon synergy. This work has achieved a multifunctional integration of mechanical properties, efficient flame retardancy, and chemical degradation, providing new ideas for the development of multi-functional biodegradable polymers.
研究领域:
高分子材料
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阻燃化学
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生物可降解材料
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材料科学
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高分子化学
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环境友好材料
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高影响因子
FOOD RESEARCH INTERNATIONAL
·
2026
·
IF 8.8
Yunge Zhang,Mi Li,Yuanchang Cao,Jian Ju,Qingmin Chen,Yanli Ma,Cuicui Li
Novel biodegradable bilayer film with unidirectional release. • PLA/ZnO/MgO outer layer improves barrier and UV-blocking. • Inner gelatin/EUG-THY layer ensures long-term antimicrobial activity. Fresh cucumbers are highly perishable due to moisture loss, microbial infection, and oxidative deterioration. In this study, a biodegradable bilayer active packaging film with unidirectional release was developed for cucumber preservation. The outer PLA layer was reinforced with 2 wt% of a 1:1 ZnO/MgO nanoparticle mixture, exhibiting enhanced hydrophobicity, mechanical strength (tensile strength 62.75 MPa), reduced water vapor permeability (88.7 g/m 2 ·24 h), and excellent UV-blocking. The inner layer was prepared by electrospinning gelatin loaded with 0.2–0.4 wt% eugenol (EUG) and thymol (THY). Unidirectional release evaluation showed that >92% of EUG and THY were released toward the food simulant via a non-Fickian diffusion mechanism ( n = 0.54–0.57). The films exhibited concentration-dependent antimicrobial and antioxidant activities. During 21 days of storage at 4 °C, cucumbers packaged with the EUG/THY-loaded bilayer films showed significantly lower weight loss, reduced color deterioration, and enhanced antioxidant enzyme activities. The 0.4% EUG/THY formulation extended cucumber shelf life to 18–20 days. This bilayer design offers a promising strategy for eco-friendly active packaging with unidirectional release for fresh produce preservation. Download: Download high-res image (174KB) Download: Download full-size image
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
·
IF 8.5
Qian Zhang,Hongwei Wang,Mengxing Chen,Lihong Wang,Xin Che
Infectious burn wounds are characterized by substantial exudate and inflammation. Ordinary wound dressings struggle to absorb substantial exudate. In this study, a color-changeable and separable polylactic acid/polyvinylpyrrolidone/chitosan tri-layer self-pumping dressing containing astragalus polysaccharide was developed. The dressing had an outer layer of polyacrylonitrile/polyvinylpyrrolidone/CoCl 2 nanofiber, a middle layer of polylactic acid/polyvinylpyrrolidone/chitosan nanofiber, and an inner astragalus polysaccharide drug-carrying layer. It could unidirectionally absorb wound exudate and change color after absorbing exudate. In addition, after absorbing the exudate, the outer layer of the dressing could be separated, the remaining double layers consisted of a drug layer and antimicrobial chitosan promoted wound healing and reduced infection. The water absorption rate of the tri-layer nanofibers reached 2770.70 ± 122 % per time, and the water vapor transmission rate was 4585.99 ± 65 g∙m −2 ∙day −1 . The nanofiber dressing promoted the proliferation, migration, and adhesion of L929 cells. After treating burn-infected rats with this dressing for 14 days, the rats' collagen content and anti-inflammatory levels increased. In conclusion, the color-changeable and separable polylactic acid/polyvinylpyrrolidone/chitosan tri-layer self-pumping dressing containing astragalus developed in this study can effectively accelerate wound healing.
研究领域:
生物医学工程
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纳米技术
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药学
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伤口护理
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高分子科学
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炎症研究
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组织工程
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PubMed
高影响因子
Sustainable Materials and Technologies
·
2024
·
IF 8.6
Yadong Wang,Yingao Zhang,Li Ma,Jingjing Gao,Hui Ge,Zongmin Zhu
Traditional intumescent flame retardants (IFR) composed of ammonium phosphate (APP) and charring agent can endow polymers with excellent flame retardancy, but always at the cost of sacrificing the mechanical properties of polymers. In this work, we designed and synthesized a charring agent (named as PDM, 70% of residual mass at 700 °C) with super strong carbonization , and mixed it with APP to construct an IFR. This IFR endowed polylactic acid (PLA) with excellent flame retardancy under ultra-low loading conditions, while also enhancing and toughening PLA. Adding only 2 wt% of APP/PDM resulted in a UL-94 V-0 level and a 29.3% of limiting oxygen index (LOI), as well as a reduction of 40.4%, 39.6% and 34.1% in the peak of heat release (pHRR), total heat release (THR) and total smoke release (TSP) for PLA. In addition, the tensile and impact strengths were improved to 59.2 MPa and 13.1 kJ/m 2 from 58.8 MPa and 7.7 kJ/m 2 of pure PLA, respectively. The synergistic carbonization effect between PDM and APP was a key factor contributing to PLA's exceptional flame retardancy and smoke suppression performance.
研究领域:
材料科学
·
高分子化学
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Tianliang Dai,Lina Wang,Juming Yao,Guocheng Zhu,Baochun Guo,Jiri Militk,Dana Kremenakova,Ming Zhang
Janus membranes are widely used in fields such as oil-water separation and wound dressings due to their asymmetric wetting properties. However, the weak interface binding force between the hydrophobic and hydrophilic layers can affect the liquid transport performance and membrane separation. In this study, we have reported a method using self-induced crystallization to grow shish-kebab (SK) structures in electrospinning polylactic acid-based fiber membranes. Peel testing revealed that the peel load after induced crystallization increased from 0 to 0.05 N to 0.05–0.15 N, and the time for droplets to penetrate from the hydrophobic side to the hydrophilic side decreased from 16S to 3S. This indicates that SK structures can enhance the adhesion between the hydrophilic and hydrophobic interface, as well as facilitating droplet transport. Through the oil-water separation experiment, it was discovered that the presence of SK structures can filter out more microemulsions. For different emulsions (kerosene, petroleum, n-hexane, petroleum ether, tea tree oil), the separation efficiency of Janus-SK membrane increased by 1.67 %, 2.5 %, 3.0 %, 9.7 %, 4.3 %, respectively. The development of Janus membranes has been provided with a new direction.
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高影响因子
Polymers
·
2021
·Vol. 13
·期 22
·3962
·
IF 4.329
Abdul Shakoor Shar,Caili Zhang,Xieqing Song,Yunxuan Weng,Qiuyue Du
Polymer/clay composites are an innovative class of materials. In this study, we present a facile method for the preparation of biodegradable and robust PLA/organomodified montmorillonite (OMMT) composite films with excellent gas barrier performance. When the design of PLA/OMMT composite films, in addition to making OMMT have good intercalation effect in the matrix, the compatibility of intercalating polymer and matrix should also be considered. In this work, two polymers with high gas barrier properties, namely poly(vinyl alcohol) (PVA) and ethylene vinyl alcohol copolymer (EVOH), were selected to intercalate OMMT. The morphology and microstructures of the prepared PLA/PVA/OMMT and PLA/EVOH/OMMT composites were characterized by the X-ray diffraction measurement, scanning electron microscopy, and differential scanning calorimetry. It was shown that the good dispersibility of PVA in the PLA matrix, rather than the intercalation effect, was responsible for the improved gas barrier and mechanical properties of PLA/PVA/OMMT composite. The elongation at break increases from 4.5% to 22.7% when 1 wt % PVA is added to PLA/OMMT. Moreover, gas barrier of PLA/PVA1/OMMT measured as O2permeability is 52.8% higher than that of neat PLA. This work provides a route to intercalate OMMT interlayer with high gas barrier polymers and thus can be a useful reference to fabricate PLA/OMMT composites with improved gas barrier and mechanical properties. A comparison of oxygen permeabilities with existing commercial packaging films indicates that the biodegradable PLA/PVA/OMMT may serve as a viable substitute for packaging film applications.Keywords:poly(lactic acid);OMMT;gas barrier films;nanocomposites
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2021
·
IF 5.645
Qing Zhang,Ruoteng Ma,Lisha Ma,Lili Zhang,Yimin Fan,Zhiguo Wang
It is important to improve the interface compatibility between lignocelluloses (LCs) and biodegradable polylactic acid (PLA) for the preparation of strong composite materials. In the current study, esterified lignocellulose nanofibers (LCNFs) with high yield were prepared from LCs with different lignin contents (0.83–17.45 %) by swelling with a lactic acid/choline chloride deep eutectic solvent (LA/ChCl DES) at 100 ℃ for 3 h followed by mechanical colloid milling. Esterification occurred along with nanofibrillation of the LCs to obtain LCNFs having ester bonds with diameters mostly less than 100 nm. Lignin remained in the LCNFs with various contents. Uniform LCNF/PLA composites were prepared by a direct blending method. Lignin in the esterified LCNFs acted as an interface adhesive and played a key role in increasing the LCNFs interface compatibility with PLA, as well as strengthening the mechanical properties of the composites. The optimized flexural properties of the composites reached a maximum value of 204.5 MPa when 20 % LCNF (containing 10.92 % lignin) was added, which was 120.6 % higher than that of pure PLA. The prepared high-strength biodegradable composites have broad application prospects and great potential to replace non-degradable plastics.
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高影响因子
Polymers
·
2020
·Vol. 12
·期 1
·120
·
IF 3.426
Lu Gan,Aobo Geng,Ying Wu,Linjie Wang,Xingyu Fang,Lijie Xu,Changtong Mei
In the present study, flexible and conductive nanofiber membranes were prepared by coating PLA nanofibrous scaffolds with carbon nanotubes and silver nanoparticles. The morphology and structure of the prepared membrane was characterized, as well as its mechanical properties, electrical sensing behavior during consecutive stretching-releasing cycles and human motion detecting performance. Furthermore, the antibacterial properties of the membrane was also investigated. Due to the synergistic and interconnected three-dimensional (3D) conductive networks, formed by carbon nanotubes and silver nanoparticles, the membrane exhibited repeatable and durable strain-dependent sensitivity. Further, the prepared membrane could accurately detect the motions of different body parts. Accompanied with promising antibacterial properties and washing fastness, the prepared flexible and conductive membrane provides great application potential as a wearable fabric for real-time body motion sensing.Keywords:PLA nanofiber;flexible membrane;carbon nanotubes;silver;antibacterial properties;electrical properties
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高影响因子
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