JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 134
·期 17
·
IF 1.86
Yanmei Guo,Jun Shao,Haoqing Hou
Linear poly( d -lactide) (PDLA) with various molecular weights is synthesized and incorporated into commercial poly( l -lactide) (PLLA) with different optical purities. And then, the crystallization, mechanical and thermal properties of the PLLA and PLLA/PDLA cast films are investigated. In the PLLA and PDLA/PLLA specimens with lower optical purity, few homochiral crystallites (HC) form in all the specimens and only a small amount of PLA stereocomplex crystallites (SC) are observed in the blends. The elongation at break of all the specimens is extraordinary high, >300%. Dynamic mechanical analyses indicate that the destruction temperature increases at first, and then depresses as enlarging the molecular weight of PDLA in these blends. For the PLLA and PLLA/PDLA with higher optical purity, more content of HC develops in neat PLLA, and both SC and HC produce in the PLLA/PDLA specimens. However, the strains of neat specimens and binary blends are much lower than that of specimens with lower optical purity. The specimens with higher optical purity exhibit higher destruction temperatures and lower loss factors. The high content of crystals (SC and HC) would act as the physical cross-linking points and provide a key factor to impede the deformation of neat PLLA and binary blends during stretching, which should result in the fragile behavior of the PLLA and PLLA/PDLA blends with higher optical purity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44730.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2019
·Vol. 30
·期 4
·963-972
·
IF 2.162
Sheng Xiang,Lidong Feng,Xinchao Bian,Bao Zhang,Bin Sun,Yanlong Liu,Gao Li,Xuesi Chen
To obtain an effective compatibilizer for the blends of poly(L-lactide) (PLLA) and poly(ε-caprolactone) (PCL), the diblock copolymers PCL- b -PLLA with different ratios of PCL/PLLA (CL/LA) and different molecular weights ( M n ) were synthesized by ring-opening polymerization (ROP) of L-lactide with monohydric poly(ε-caprolactone) (PCL-OH) as a macro-initiator. These copolymers were melt blended with PLLA/PCL (80/20) blend at contents between 3.0 and 20 phr (parts per hundred resin), and the effects of added PCL- b -PLLA on the mechanical, morphological, rheological, and thermodynamic properties of the PLLA/PCL/PCL- b -PLLA blends were investigated. The compatibility between PLLA matrix and PCL phase was enhanced with decreasing in CL/LA ratios or increasing in M n for the added PCL- b -PLLA. Moreover, the crystallinity of PLLA matrix increased because of the added compatibilizers. The PCL- b -PLLA with the ratio of CL/LA (50/50) and M n ≥ 39.0 kg/mol were effective compatibilizers for PLLA/PCL blends. When the content of PCL- b -PLLA is greater than or equal to 5 phr, the elongations at break of the PLLA/PCL/PCL- b -PLLA blends all reached approximately 180%, about 25 times more than the pristine PLLA/PCL(80/20) blend.
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
POLYMER
·
2014
·Vol. 55
·期 22
·5760-5772
·
IF 3.766
Feng Wu,Bao Zhang,Wei Yang,Zhengying Liu,Mingbo Yang
The low melt strength greatly limits the application of PLA as biodegradable package materials produced by film blowing method. Modified silica nanoparticles are introduced into PLA matrix to solve this problem in this study. To build Poly ( l -lactide) nanocomposites successfully, two kinds of convenient and efficient methods are conducted to synthesize well-defined topological PLLA grafted SiO 2 nanoparticle. One is the ring-opening of l -lactide (Grafting from), and another is nucleophilic addition reaction (Grafting to). The structure, molecular weight of grafted PLLA chains, grafting density, and the thermal decomposition behavior of the nanoparticles prepared by different methods are characterized. By varying the contents of the initiator SiO 2 and the molecular weight of the reacted PLA chains, high density-low molecular weight PLLA grafted SiO 2 are obtained in “grafting from” while high molecular weight-low grafting density PLLA grafted SiO 2 are synthesized in “grafting to”. It is exactly in good agreement with the theoretic model. The spatial distribution of nanoparticles as well as the interaction force between nanoparticles and matrix is critical important to structuring bionanocomposites with desirable properties. So the two kinds of synthesized nanoparticles are introduced into PLA matrix in our contribution to evaluate these two factors, respectively. The TEM and SEM results both reveal the uniform dispersion of nanoparticles after modified. While the extension and shear rheology results show that the long grafted chains covalently connected on the surface of the silica via “grafting to” contribute more to enhance the melt strength of PLA. Meanwhile, stabilized PLA nanocomposites films with modified silica via “grafting to” method are successfully blown base on these researches. The research in this work constitutes a robust way to design melt-strengthen PLA/SiO 2 nanocomposites.
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DOI
高影响因子
ACS Applied Polymer Materials
·
2021
·
IF 4.089
Wenyuan Xie,Chenguang Jiang,Xing Yu,Xinyu Shi,Shubin Wang,Yu Sun,Ming Yin,Defeng Wu
Biodegradable polymersomes that can potentially be employed in drug delivery systems were fabricated by blending poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide) (PLLA-PEG-PLLA) and poly(d-lactide)-b-poly(ethylene glycol)-b-poly(d-lactide) (PDLA-PEG-PDLA) block copolymers in a weight ratio of 1:1 in an aqueous solution. A series of amphiphilic PLLA-PEG-PLLA and PDLA-PEG-PDLA triblock copolymers were synthesized with different hydrophobic chain lengths through ring-opening polymerization. The self-assembly of pure PLLA-PEG-PLLA and an equimolar mixture of enantiomers of PLLA-PEG-PLLA and PDLA-PEG-PDLA was investigated by transmission electron microscopy, X-ray diffraction, and dynamic light scattering. Various nanostructures including spherical micelles, worm-like micelles, and vesicles were obtained by controlling the hydrophobic chain length and the incubation temperature. In the pure PLLA-PEG-PLLA systems, the hydrophobic–hydrophilic balance dominated the self-assembled morphologies. In equimolar enantiomer mixtures, self-assembled morphologies were greatly affected by the formation of the PLLA-PDLA stereocomplex (SC). There was an inverse correlation between the SC crystallinity and the curvature of the self-assembled structures─the higher the SC content, the smaller the curvature. This rule was not applicable when the SC content was too high (≳50%), which produced spherical micelles as the main nanostructures. Since the SC-induced self-assembly could be controlled by changing the incubation temperature, the polymersomes can potentially be used in many applications, such as nanoreactors and nanovehicles.
研究领域:
材料科学
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药物递送系统
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Materials and Technologies
·
2023
·
IF 9.6
Pei Feng,Saipu Shen,Yang Shuai,Shuping Peng,Cijun Shuai,Shijie Chen
The interfacial interaction between poly (l-lactic acid) (PLLA) and poly (glycolic acid) (PGA) is poor although the blending of PLLA and PGA may combine the advantages of both, which seriously affects the mechanical properties of PLLA/PGA bone scaffold. In this study, PLLA chains were grafted onto graphene oxide (GO) by ring-opening polymerization reaction, and the modified GO was used as nanofiller to increase the interfacial interaction for PLLA/PGA scaffold fabricated by selective laser sintering (SLS). The result indicated that GO grafted with PLLA chains reduced the interfacial tension between GO and PLLA from 24.09 mN/m to 3.74 mN/m, thus drawing GO from PGA phase to the interface between PLLA and PGA. The GO at the interface hindered the coalescence of PGA phase through the repulsive forces and facilitated the breakup of the PGA phase, which increased the contact surface area between PLLA and PGA, and thereby enhancing the interfacial interaction. Consequently, the tensile and compressive strength of the PLLA/PGA scaffold containing 1 wt% the PLLA-grafted GO, on which L-LA ring-opening polymerized for 24 h, were increased by 44.64% and 69.65%, respectively, compared with PLLA/PGA scaffold. Besides, the cell adhesion and fluorescence experiments demonstrated that the bone scaffold had good cytocompatibility for cell adhesion, migration and proliferation.
研究领域:
生物材料学
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组织工程学
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产品关联
DOI
高影响因子
Coatings
·
2022
·Vol. 12
·期 6
·718
·
IF 3.236
Yaoting He,Jiafei Yan,Xuzhao He,Wenjian Weng,Kui Cheng
In this work, nanocomposite membranes based on graphene and polylactide were evaluated for mechanical properties and biocompatibility. Single-layer graphene (SLG), graphene nanosheets (GNS), and poly L-lactic acid (PLLA) were prepared through layer-by-layer deposition and homogeneous mixing. The results revealed that PLLA/SLG nanocomposites and PLLA/GNS nanocomposites could show enhanced mechanical properties and biocompatibility. The addition of a tiny amount of SLG significantly improved Young’s modulus and tensile strength of the PLLA matrix by 15.9% and 32.8% respectively, while the addition of the same mass ratio of GNS boosted the elongation at break of the PLLA matrix by 79.7%. These results were ascribed to the crystallinity and interfacial interaction differences resulting from graphene incorporation. Also, improved biocompatibility was observed with graphene incorporation. Such nanocomposites membranes showed a lot of potential as environment-friendly and biomedical materials.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2019
·
IF 4.959
Cijun Shuai,Jun Zan,Youwen Yang,Shuping Peng,Wenjing Yang,Fangwei Qi,Lida Shen,Zongjun Tian
The poor interfacial bonding and resultant agglomeration of nanoparticles in polymer-based composite severely deteriorated their reinforcement effect. In this work, MgO nanoparticles (MgO-NPs) were surface modified with Poly (L-lactic acid- co -malic acid) (PLMA) to improve the interfacial compatibility in Poly-l-lactic acid (PLLA) scaffold manufactured by selective laser sintering. PLMA possess a hydrophilic end with carboxyl group (comes from the malic acid) and an l-lactic acid chain. On one hand, the carboxyl group was able to form hydrogen bonding with the hydroxyl groups of MgO-NPs. On the other hand, the l-lactic acid chain containing the hydroxyl groups could react with the carboxyl group of PLLA. Results revealed that the scaffold exhibited significantly enhanced compressive strength and modulus by 47.1% and 237.7%, respectively, which could be ascribed to the enhanced interfacial bonding between PLLA and MgO-NPs, as well as the rigid particle reinforcement. In addition, the scaffold was favorable for cell adhesion, proliferation and differentiation, owing to the improved hydrophilic and suitable pH environment. It was suggested the scaffold was a promising material for bone repair application.
研究领域:
生物材料学
·
组织工程学
✓ 已验证
产品关联
DOI
PubMed
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
✓ 已验证
DOI
高影响因子
Biomaterials Research
·
2022
·Vol. 26
·期 1
·1-13
·
IF 15.863
Shuai Cijun,Chen Xuan,He Chongxian,Qian Guowen,Shuai Yang,Peng Shuping,Deng Youwen,Yang Wenjing
Background Fe 3 O 4 nanoparticles are highly desired for constructing endogenous magnetic microenvironment in scaffold to accelerate bone regeneration due to their superior magnetism. However, their random arrangement easily leads to mutual consumption of magnetic poles, thereby weakening the magnetic stimulation effect. Methods In this study, magnetic nanochains are synthesized by magnetic-field-guided interface co-assembly of Fe 3 O 4 nanoparticles. In detail, multiple Fe 3 O 4 nanoparticles are aligned along the direction of magnetic force lines and are connected in series to form nanochain structures under an external magnetic field. Subsequently, the nanochain structures are covered and fixed by depositing a thin layer of silica (SiO 2 ), and consequently forming linear magnetic nanochains (Fe 3 O 4 @SiO 2 ). The Fe 3 O 4 @SiO 2 nanochains are then incorporated into poly l-lactic acid (PLLA) scaffold prepared by selective laser sintering technology. Results The results show that the Fe 3 O 4 @SiO 2 nanochains with unique core–shell structure are successfully constructed. Meanwhile, the orderly assembly of nanoparticles in the Fe 3 O 4 @SiO 2 nanochains enable to form magnetic energy coupling and obtain a highly magnetic micro-field. The in vitro tests indicate that the PLLA/Fe 3 O 4 @SiO 2 scaffolds exhibit superior capacity in enhancing cell activity, improving osteogenesis-related gene expressions, and inducing cell mineralization compared with PLLA and PLLA/Fe 3 O 4 scaffolds. Conclusion In short, the Fe 3 O 4 @SiO 2 nanochains endow scaffolds with good magnetism and cytocompatibility, which have great potential in accelerating bone repair.
研究领域:
材料科学
·
生物材料
·
组织工程
✓ 已验证
DOI
PubMed
高影响因子
Materials
·
2024
·Vol. 17
·期 15
·3773
·
IF 3.1
Zhu Liu,Yufu Zheng,Lizhong Lin,Xiaofei Liu,Na Qiang
Electrospinning technology is widely used for preparing biological tissue engineering scaffolds because of its advantages of simple preparation, accurate process parameters, and easy control. Poly(L-lactide) (PLLA) is regarded as a promising biomass-based polymer for use in electrospinning. The incorporation of Fe3O4nanoparticles (NPs) could improve the osteogenic differentiation and proliferation of cells in the presence or absence of a static magnetic field (SMF). In this work, these two materials were blended together to obtain electrospun samples with better dispersibility and improved magnetic properties. First, composite PLLA and Fe3O4NP fibers were prepared by means of electrospinning. The influence of electrospinning conditions on the morphology of the composite fibers was then discussed. Changes in magnetic properties and thermal stability resulting from the use of different PLLA/Fe3O4mass ratios were also considered. Next, the morphology, crystal state, thermodynamic properties, and magnetic properties of the electrospun samples were determined using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and vibration sample magnetization (VSM). The results showed that the fibers prepared using PLLA withMn= 170,000 exhibited good morphology when electrospun at 12 KV. The magnetic properties of PLLA/Fe3O4composite electrospun fibers increased with the NP content, with the exception of thermal stability. The results of the present study may help to promote the further development of PLLA/Fe3O4composite materials in the biomedical field.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biomaterials Advances
·
2026
·
IF 6.7
Zi Lin Li,Gang Wang,Yilin Ding,Qiyuan Dai,Huitong Luo,Zhifeng Shi,Xinrong Xu,Xiaodong Cao
Poly-L-lactic acid (PLLA) microspheres have been successfully commercialized for skin rejuvenation. However, the inherent material properties, notably their hydrophobic surface and the acidic byproducts generated during degradation, have the potential to incite inflammatory responses and compromise long-term efficacy in tissue regeneration. In order to overcome these limitations, integrating biodegradable polymers with bioactive components are highly desirable to synergistically improve biocompatibility and actively stimulate tissue regeneration. In this study, we engineered novel composite microspheres that integrate PLLA with bioactive glass (BG). In vitro, PLLA/BG composite microspheres functioned as potent biomimetic cues, dramatically boosting cell biological behaviors of human foreskin fibroblasts (HFFs). Furthermore, the microspheres upregulated the expression of critical extracellular matrix (ECM) proteins, which underscores their potential to drive skin regeneration, and orchestrated a pro-regenerative response by upregulating key signaling factors, including transforming growth factor β1 (TGF-β1) and PDZ and LIM domain 5 (PDLIM5). The microspheres effectively polarized macrophages toward the pro-regenerative M2 phenotype and enhanced angiogenesis. In vivo experiments using a wrinkle-induced mouse model demonstrated that PLLA/BG composite microspheres significantly suppressed wrinkle formation, enhanced the deposition of ECM proteins, and stimulated new blood vessel formation. Collectively, our results established that PLLA/BG composite microspheres could modulate the skin microenvironment and achieve rejuvenation of aging skin.
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science
·
2026
·
IF 14.1
Longfei Li,Juwei Yang,Yiqian Wang,Qiao Yu,Zhenmin Fan,Chang Zhu,Ming Yin,Wei Hua,Zhou Li
The development of flexible electronic devices necessitates materials with high piezoelectric performance. Poly(L-lactic acid) (PLLA) nanofiber-based piezoelectric membranes hold promise for self-powered health monitoring and tissue repair, yet their intrinsic piezoelectric performance remains insufficient for practical applications. Here, we develop a multi-path strategy to enhance the piezoelectric properties through crystallography and hierarchical design of PLLA fibers. We also demonstrate that incorporating high-aspect-ratio needle-like hydroxyapatite (HAp) into PLLA optimizes crystallinity and enhances piezoelectric output. Building upon this, we construct PLLA-HAp/PLLA composite fiber membranes with topological structures to further amplify the piezoelectric effect. Notably, low-concentration HAp dispersed within random PLLA fibers induces stress concentration at the interface with aligned PLLA fibers, resulting in satisfactory piezoelectric performance. In the impact mode and bending mode, the piezoelectric output is approximately 6 and 14 times that of pure PLLA fiber, respectively. The optimized fiber membranes demonstrated excellent potential for monitoring human physiological activities, as validated by subsequent experiments that successfully recorded porcine joint movements and heart rates. This piezoelectric enhancement strategy offers a new approach for next-generation high-performance piezoelectric devices, with broad applicability in health monitoring and tissue engineering.
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）