POLYMER DEGRADATION AND STABILITY
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2026
·
IF 8.1
Lunhe Wang,Pengcheng Zhang,Jun Lu,Juanjuan Su,Jian Han
To simultaneously overcome the low heat resistance and insufficient barrier properties of biaxially oriented polylactic acid (BO-PLA) film, this study concurrently incorporates polypropylene carbonate (PPC) and epoxidized soybean oil (ESO) to regulate the crystalline structure and phase morphology of PLLA/PDLA (LD) mixtures. ESO enhances compatibility between PPC dispersed phase and the LD matrix through reactive compatibilization while also establishing a branched topological molecular structure. This reinforces molecular chain entanglement and increases melt strength of LD-PG blend. During biaxial stretching, PPC and ESO synergistically elevate the alternative folding and stacking of enantiomeric PLA chains, through joint plasticization, enhanced intermolecular interactions, and reinforced entanglement. BO-LD-PG 4 × 4 film achieves a total crystallinity of 47.6% and SC crystallinity of 27.2%. Larger HC lamellas and smaller SC lamellas form highly oriented and interlocked fibrous structures, creating a dense crystalline network with shish-kebab-like crystalline distributed throughout, which significantly improves the heat resistance of BO-LD-PG 4 × 4 film with a shrinkage rate as low as 6.3% at 150 °C. Concurrently, the PPC nanophase and SC/HC crystalline network structure jointly enhance the barrier properties of BO-LD-PG 4 × 4 films, achieving as pH ₂O of 2.96 × 10⁻¹⁴ g · cm/cm² · s · Pa and P O₂ of 1.4 × 10⁻² cm³ · cm/m² · h · 0.1 MPa. This work not only provides an effective strategy for preparing high-performance fully biodegradable packaging materials but also sheds light on the structural evolution mechanisms of LD blends during biaxially stretching.
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Yun Zhong,Tiantian Li,Haibo Lin,Lei Zhang,Zhu Xiong,Qile Fang,Guoying Zhang,Fu Liu
In this work, we report the continuous flowing catalysis of meso-/macro-porous microspheres confining Au nanoparticles based on Poly ( l -lactic acid)/Poly (D-lactic acid) (PDLA/PLLA) stereo-complex membrane. Plentiful meso-/macro-porous microspheres (1–2 µm diameter) were assembled inside the stereo-complex Poly(lactic acid) (PLA) membrane through the phase inversion, which were thought to play a critical role on robustly capturing and confining Au nanoparticles (30–40 nm diameter) with the loading content of 1.56 g/m 2 , as demonstrated by the SEM, TEM, EDX and XPS. The Au nanoparticles-loaded stereo-complex PLA membrane exhibits an instantaneous reduction for 4-nitrophenol in a continuous flowing operation with the dynamic reactive constant 386 min −1 under the water flux of 262.8–1440 L/m 2 ·h, which was ∼2900 fold higher than the static catalytic. Moreover, the catalytic membrane keeps above 90% conversion even after 140 min continuous flowing. In addition, The Au nanoparticles-loaded stereo-complex PLA membrane demonstrated the better bovine serum albumin (BSA) antifouling and ink colloid rejection. All results verified that the stereo-complex PLA membrane provided a feasible platform for meso-/macro-porous microspheres confining Au nanoparticles as high efficient heterogeneous catalysts. The proposed strategy could be extended to other robust heterogeneous catalysts for membrane catalytic applications.
研究领域:
材料科学
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催化化学
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环境工程
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DOI
高影响因子
POLYMER
·
2024
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IF 4.1
Shitong Wang,Kai Huang,Wenjing Shi,Jiajia Mo,Honghui Shi,Chuntai Liu,Baobao Chang
Stereocomplex crystal (SC) in poly( l -lactide) (PLLA)/poly( d -lactide) (PDLA) can significantly improve the heat resistance and mechanical performance of poly(lactic acid). In this work, a selective degradation method is developed to etch the PLLA/PDLA blend using proteinase K, and a two-phase co-continuous structure is observed directly using scanning electron microscope. Meanwhile, the evolution of the microphase morphology, inter-chain interaction, chains orientation, and crystallization of un-crosslinked and crosslinked blends during solid-state stretching, as well as the formation of SC during heating/annealing are comprehensively investigated. Results showed that the phase separation in the stretched blend could be drastically restricted by crosslinking; during stretching a blue-shift of 2995 cm −1 band shows up for both crosslinked and un-crosslinked blends as a result of the dipole-dipole coupling interaction between CH 3 and CH 3 , while the hydrogen bond interaction between CH 3 and C O is absent; only mesophase or homocrystal (HC) is formed in the stretching temperature range of 60∼105 °C; the critical strain for HC formation is advanced and the orientation of chains is enhanced by crosslinking under the same stretching condition. In the last, benefiting from the greatly reduced microphase size (namely enlarged interfacial area between PLLA and PDLA) and enhanced chains orientation, the crystallization rate of SC is accelerated during annealing, and the ultimate crystallinity of SC is elevated in the crosslinked blend.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 68
·63597-63606
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IF 3.289
Shasha Zhao,Xiaoshan Fan,Xiaoyan Li,Xianglin Lv,Weiwei Zhang,Zhiguo Hu
Y-Shaped amphiphilic copolymers (zwitterionic-(PLLA2.5K)2 and MPEG-(PDLA2.5K)2) were simply synthesized through click reaction of alkyne-(PLA2.5K)2 and zwittterionic-N3 or MPEG-N3. Gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (1H NMR) were employed to characterize the composition and structure of these copolymers. The stereocomplexes were prepared from pairs zwitterionic-(PLLA2.5K)2/MPEG-(PDLA2.5K)2 (molar ratio = 1 : 1), and confirmed by differential scanning calorimeter (DSC). Furthermore the aggregation behaviors for these synthesized polymers and their stereocomplexes had been proved by fluorescence spectroscopy (PL), transmission electron microscopy (TEM), dynamic light scattering (DLS) and static light scattering (SLS), and zeta potential. Their critical micelle concentration (CMC) obtained by PL was 0.0213 mg mL−1 for zwitterionic-(PLLA2.5K)2/MPEG1.9K-(PDLA2.5K)2 and 0.1265 mg mL−1 for zwitterionic-(PLLA2.5K)2/MPEG5K-(PDLA2.5K)2. The stereocomplexes could self-assemble into spherical micelles with diameters of 76 nm (zwitterionic-(PLLA2.5K)2/MPEG1.9K-(PDLA2.5K)2) and 89 nm (zwitterionic-(PLLA2.5K)2/MPEG5K-(PDLA2.5K)2) respectively. The biocompatibility of these copolymers and their stereocomplexes was evaluated with relatively low cytotoxicity. The DOX-loaded micelles of the stereocomplexes had a higher drug loading content and encapsulation efficiency, and could release DOX in a controlled manner. Therefore, the new stereocomplex zwitterionic-(PLLA)2/MPEG-(PDLA)2 has great potential as a hydrophobic drug nanocarrier.
研究领域:
生物材料
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药物递送系统
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高分子化学
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DOI
高影响因子
CRYSTENGCOMM
·
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
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高分子化学
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DOI
高影响因子
LANGMUIR
·
2022
·
IF 4.331
Mingwei Guo,Zhifeng Zhao,Zhongyuan Xie,Weixin Wu,Wenjing Wu,Qinwei Gao
The isothermal crystallization behavior and corresponding morphology evolution of poly(d-lactic acid) (PDLA) blends with PLLA6.7k or MPEG-b-PLLA6.7k-g-glucose with different architectures and different PLLA-grafted copolymer contents were investigated. The formation of stereocomplexes (SCs) in between the chain branched structure of MPEG-b-PLLA6.7k-g-glucose and PDLA chains acting as the physical crosslinking points slows down the motion of PDLA chains, but the SCs could act as a heterogeneous nucleating agent for the late formation of homocrystals (HCs) in the blend system, accelerating the crystallization kinetics of HCs through enhancing the nucleation density. For PDLA/MPEG-b-PLLA6.7k-g-glucose blends, the mobility of SCs in the blend system and the nucleation density of SCs in the blends exhibit oppositional behavior during the isothermal crystallization at a Tc of 130 °C. The evolution of the crystal growth and structure during the isothermal crystallization process by rheometry has revealed the interesting role of the branched chains of MPEG-b-PLLA6.7k-g-glucose in the mechanism of the crystallization in PDLA blends.
研究领域:
材料科学
·
高分子化学
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DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 39
·28753-28767
·
IF 3.9
Yu Hu,Tian Lan,Ji Li,Lingjun Li,Jizheng Song
Cantharidin (CTD) has been widely used to treat hepatocellular carcinoma (HCC) in clinical practice. However, the current CTD preparations may induce hepatic and renal damage due to their non-specific distribution. Therefore, redox-sensitive polymer Pluronic F127-disulfide bond-poly(D,L-lactide) (F127-SS-PDLA) and active targeting polymer F127-glycyrrhetinic acid (F127-GA) were synthesized to prepare mixed micelles (GA/F127-SS-PDLA/CTD) for effective delivery of CTD. Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy were used to verify the successful synthesis of F127-SS-PDLA and F127-GA. During the preparation, this study was the first to screen the density of GA by cellular uptake assay. The results indicated that mixed micelles with 10% and 15% F127-GA (weight fraction) exhibited superior cellular uptake in comparison to micelles with 5% and 20% F127-GA. GA/F127-SS-PDLA/CTD micelles prepared by thin film hydration method demonstrated excellent drug loading capacity for CTD (16.12 ± 0.11%). The particle size and zeta potential of GA/F127-SS-PDLA/CTD micelles were 85.17 ± 1.24 nm and −11.71 ± 0.86 mV, respectively. Hemolysis and stability assay showed that the mixed micelles had good blood compatibility and could remain stable for 30 days at 4 °C. The redox-sensitivity of GA/F127-SS-PDLA/CTD micelles in vitro was verified under reducing conditions through dynamic light scattering (DLS) and an in vitro drug release experiment, which showed obvious particle size variation and rapid drug release ability. In cellular experiments, GA/F127-SS-PDLA/CTD micelles could induce superior cytotoxicity, apoptosis and intracellular reactive oxygen species (ROS) levels compared with free CTD, non-sensitive F127-PDLA/CTD micelles and redox-sensitive F127-SS-PDLA/CTD micelles. The cellular uptake ability of nile red-labeled GA/F127-SS-PDLA micelles, which was evaluated via fluorescent microscope and flow cytometry, indicated that the modification of GA significantly increased micelle uptake in HepG-2 cells. Consequently, GA/F127-SS-PDLA/CTD micelles could be considered as a satisfactory drug administration strategy in the treatment of HCC.
研究领域:
药学
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生物医学工程
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肿瘤学
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材料科学
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）