纳米粒子改性聚酰亚胺现状及进展

由于聚酰亚胺(PI)材料存在亲水性较弱、加工成型性较难、电导率较低等缺陷，需要通过纳米粒子改性聚酰亚胺改善其性能。基于不同纳米粒子改性聚酰亚胺，综述并评论了国内外聚酰亚胺纳米复合材料的研究现状，阐述了有机纳米粒子(CNC、FEP)、无机纳米粒子(陶瓷材料、金属纳米粒子、蜂窝芯材)、有机-无机纳米粒子(POSS、MWCNTs-COOH、OGO)复合改性聚酰亚胺性能的原理和效果，分析了聚酰亚胺复合杂化过程中面临的问题和改进方法，结合目前聚酰亚胺复合材料发展集中在合成工艺改进、填料优化改性等方面的研究趋势，提出了聚酰亚胺未来的研究方向。     

羟基磷灰石/聚乳酸类复合材料

聚乳酸(PLA)类高分子是一类重要的生物降解聚合物，羟基磷灰石(HA)是人体骨骼的基本成分，以PLA类高分子为基体、以HA为增强材料的HA／PLA复合材料是复合生物材料中无机／有机复合材料的典型代表，其具有良好的生物相客性，在骨修复领域有重要的应用。笔者在介绍HA／PLA类复合材料的制备、性能和应用等研究近况的基础上，指出使用新型的复合工艺，采用纳米级和改性的HA增强是其发展趋势。     

纳米CaCO3/丁苯胶乳增韧柔性木塑复合材料的研究

柔性木塑复合材料作为一种柔软的、可弯曲的、可卷曲的新型木塑复合材料,在铺地材料、室内装饰等领域有广泛的发展和应用前景。以纳米CaCO₃和丁苯胶乳采用共沉积法制备纳米级复合粒子,对柔性木塑复合材料增韧改性。通过傅里叶红外光谱、扫描电镜等对其化学结构、断面形貌和力学性能等进行表征。结果表明,纳米级复合粒子成功制备,且当纳米CaCO₃与丁苯胶乳质量比为5∶3时,综合力学性能达到最佳。冲击强度、拉伸强度、断裂伸长率对比未经改性的柔性木塑复合材料分别提升了160.5%、56.8%、156.5%,复合材料韧性得到了大幅度提升。     

纳米粒子改性丙烯酸酯制备复合材料

作为分散相的纳米粒子以独立的相态形式通过改性,分散到作为连续相的丙烯酸酯聚合物基体中形成一种既保留无机材料的热稳定性与硬度,又兼具聚合物韧性与介电性能的复合材料,该过程不是无机相与有机相的简单混合,而是在纳米尺度内两相的有机复合。综述了近年来纳米粒子改性丙烯酸酯复合材料,重点介绍了纳米粒子种类、纳米粒子表面改性、复合材料制备方法及其工业应用等方面的研究成果,并对其发展方向进行了分析和展望。     

聚酯纳米复合材料研究的进展

利用纳米粒子对高分子材料进行改性可以使其性能更加优异。介绍了共混法、插层复合法等聚酯纳米复合材料的制备方法,讨论了纳米粒子改性聚合物的增韧机理,并对聚酯纳米复合材料的研究进展进行了评述。     

纳米粒子对硅橡胶的增强改性研究进展

纳米粒子和纳米复合技术对于开发新型功能复合材料具有十分重要的意义,其中纳米粒子对橡胶的复合改性为硅橡胶性能的提高提供了新的途径.评述了二氧化硅、黏土、氧化铝、碳酸钙、二氧化钛等纳米粒子对硅橡胶的物理机械性能、耐热性能、阻燃性能及耐老化性能等方面的增强改性,简述了溶胶-凝胶法、层间插入法及共混法三种纳米硅橡胶复合材料的制备方法,并指出了纳米硅橡胶复合材料的研究发展方向.     

PMMA接枝纳米ZnO复合粒子改性PVC塑料性能研究

通过原位聚合将甲基丙烯酸甲酯（MMA）接枝于纳米ZnO表面,制备了PMMA接枝纳米ZnO复合粒子,将其加入聚氯乙烯（PVC） 基体中进行改性。研究了纳米ZnO粒子在PVC基体中的分散性和PVC复合材料的力学性能,探讨了改性纳米ZnO粒子填充PVC材料的抗紫外线性能。结果表明,改性后的纳米ZnO粒子在PVC基体中分散均匀, 提高了纳米ZnO粒子与PVC基体之间的相容性,使改性PVC材料的拉伸强度达到78 MPa,比纯纳米ZnO粒子改性PVC提高了35 %;冲击强度提高了近1倍,达到13.6 kJ/m2;加入改性纳米ZnO粒子的PVC还具有明显的吸收紫外线功能。     

纳米CaCO_3增强增韧PP/弹性体复合材料的研究

采用钛酸酯偶联剂对纳米CaCO_3进行了表面接枝改性,并采用熔融共混法制备了聚丙烯(PP)/乙烯–辛烯嵌段共聚物(OBC)/纳米CaCO_3复合材料,研究了纳米CaCO_3的加入量对复合材料的力学、热力学及流变性能的影响,并观察了复合材料的断面形貌。结果表明,当改性纳米CaCO_3含量为2.5%时,复合材料的力学性能最佳,其中拉伸强度达到27.5 MPa,冲击强度达到16.1 k J/m2,进一步增加纳米CaCO_3含量时,由于纳米粒子之间发生了严重团聚使复合材料力学性能显著下降;纳米CaCO_3的加入对复合材料起到了异相成核的作用,提高了复合材料的结晶温度和结晶度;复合材料中纳米粒子的存在使其复合黏度和储能模量同时升高。     

PTFE-纳米粒子复合材料的制备及性能研究

使用硅烷偶联剂KH560对纳米Si3N4和Al2O3进行了改性,随后将其分别填充到PTFE树脂中制备了PTFE-纳米粒子复合材料,研究了不同KH560含量对复合材料密度、硬度,力学性能及摩擦磨损性能的影响。结果表明,纳米Si3N4经质量分数6%的KH560改性后,填充制备的PTFE复合材料其拉伸强度、断裂伸长率与未经改性纳米Si3N4填充复合材料相比,磨耗量高、硬度低,但密度、摩擦系数等相差不大;纳米Al2O3分别经质量分数4%的KH560改性后,对应复合材料的拉伸强度和断裂伸长率大于未改性纳米Al2O3填充复合材料,但密度、硬度、磨耗量及摩擦系数等相差不大。     

SBS纳米复合材料的制备研究现状

介绍目前国内外SBS纳米复合材料的研究现状，重点介绍用蒙脱土和白泥制备SBS纳米复合材料的原理和方法，包括蒙脱土和白泥的精制改性、蒙脱土与高聚物的复合方法、复合熔融插层法和溶液插层法蒙脱土／SBS纳米复合材料的制备以及改性白泥和改性纳米层状白泥／SBS纳米复合材料的制备。指出制备耐热聚合物纳米粒子对SBS进行填充改性或采用纳米复合技术在SBS中引入纳米无机相进行增强反应是SBS纳米复合材料的研究方向。     

3D porous HA/TCP composite scaffolds for bone tissue engineering

Calcium phosphates (apatites) are considered as a research frontier for bone regeneration applications by virtue of similarity to the mineral constituent of bone, suitable biocompatibility and remarkable osteogenesis ability. In this regard, the biodegradability and mechanical properties of monophasic apatites, typically hydroxyapatite (HA) and tricalcium phosphate (TCP), are imperfect and do not fulfill some requirements. To overcome these drawbacks, 3D porous HA/TCP composite scaffolds prepared by conventional and more recently, 3D printing techniques have shown to be promising since their bioperformance is adjustable by the HA/TCP ratio and pores. Despite the publication of several reviews on either 3D porous scaffolds or biphasic calcium phosphates (BCPs), no review paper has to our knowledge focused on 3D porous BCP scaffolds. This paper comprehensively reviews the production methods, properties, applications and modification approaches of 3D porous HA/TCP composite scaffolds for the first time. In addition, new insights are introduced towards developing HA/TCP scaffolds with more impressive bioperformance for further tissue engineering applications, including those with different interior and exterior frameworks, patient-specific specifications and drugs (or other biological factors) loading.     

Surface organo-modification of hydroxyapatites to improve PLA/HA compatibility

Polylactide/hydroxyapatite (PLA/HA) composites are promising tissue engineering materials because of the PLA biodegradability and HA as a natural bone component. PLA/HA composites without HA modification lead to mechanical failure due to the interfacial immiscibility. In this study, an effective chemical surface methodology is used to modify HA to obtain PLA/HA composites with superior mechanical properties. The HA particles are modified with fatty acids (adipic, sebacic, lauric, and linoleic) and incorporated into a PLA matrix by polymer solution casting, using chloroform as the solvent. After the HA modification, the films exhibited an improvement in tensile strength, elongation at break, and elastic modulus. Yet, the best results observed are by sebacic and adipic acid modification. These increments are attributed to a higher affinity of the organo-modified HA particles within the PLA matrix. Therefore, the development of materials for osteo-regeneration engineering based on these systems is quite promising.     

Fabrication of Hydroxyapatite/Ethylene-Vinyl Acetate/Polyamide 66 Composite Scaffolds by the Injection-Molding Method

This research investigated the injection-molding techniques to produce hydroxyapatite (HA)/ethylene-vinyl acetate (EVA)/polyamide 66 (PA66) composite scaffolds. The effects of HA, EVA, azodicarbonamide (AC) content and shot size on the mechanical properties, pore morphology, porosity and crystallization behavior of the composite scaffolds were analyzed by XRD, DSC, SEM and mechanical test. The compressive modulus and strength of the HA/EVA/PA66 scaffolds with a pore size of 200–600 µm are close to the cancellous bone. Compared with common methods to fabricate scaffolds, this process makes the fabrication of composite scaffolds come true in a rapid and convenient manner.     

Preparation and characterization of a poly(methyl methacrylate) based composite bone cement containing poly(acrylate‐co‐silane) modified hydroxyapatite nanoparticles

The purpose of this study was to study the mechanical properties of poly(methyl methacrylate) (PMMA)‐based bone cement incorporated with hydroxyapatite (HA) nanoparticles after surface modification by poly(methyl methacrylate‐co‐γ‐methacryloxypropyl timethoxysilane) [P(MMA‐co‐MPS)]. PMMA and P(MMA‐co‐MPS) were synthesized via free‐radical polymerization. P(MMA‐co‐MPS)‐modified hydroxyapatite (m‐HA) was prepared via a dehydration process between silane and HA; the bone cement was then prepared via the in situ free‐radical polymerization of methyl methacrylate in the presence of PMMA and P(MMA‐co‐MPS)–m‐HA. Fourier transform infrared (FTIR) spectroscopy, ¹H‐NMR, and gel permeation chromatography were used to characterize the P(MMA‐co‐MPS). Thermogravimetric analysis and FTIR were used as quantitative analysis methods to measure the content of P(MMA‐co‐MPS) on the surface of HA. The effect of the proportion of m‐HA in the PMMA‐based bone cement on the mechanical properties was studied with a universal material testing machine. A 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay was also carried out to determine the cytotoxicity of the composite bone cement. The results showed that the surface modification of HA greatly improved the interaction between the inorganic and organic interfaces; this enhanced the mechanical properties of bone cement for potential clinical applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40587.     

聚乳酸基复合骨组织修复材料的研究现状及进展

综述了聚乳酸（PLA）复合材料在骨组织工程材料中的研究进展;总结了国内外关于PLA复合材料的组成成分、合成工艺、加工方法及相对应的力学、生物学性能等方面的研究概况;梳理了PLA复合材料组成、结构与性能的相互关系,对PLA复合材料在骨组织修复材料中的应用发展前景进行了展望。     

Marine biological waste as a source of hydroxyapatite for bone tissue engineering applications

The demand for bone graft substitutes for orthopedics and dentistry is constantly growing due to the increase of ageing-related diseases. Synthetic hydroxyapatite (HA) is largely used as a bone graft material thanks to its biocompatibility, osteointegration, osteoconductive and osteoinductive properties and similarity to biological apatite, the main mineral component of bones and teeth. Biogenic apatite has gained attention due to its peculiar intrinsic characteristics: multi-doped ion composition and micro- and nano-scale architecture make natural-derived HA particularly promising for biomedical applications.At the same time, the growing interest in green materials is pushing towards the use of more sustainable biomaterials precursors, including re-use materials: marine waste, such as mollusk-shells, shellfish carapaces, cuttlefish bone, and fishbone have become widely studied sources of biogenic HA. Indeed, they are rich in calcium carbonate (CaCO₃), which can be converted into HA by environmentally sustainable processes. This allows the transformation of waste into valuable materials, while paying attention to the issues of sustainability and circular economy.In this review, we listed and discussed the methods to produce HA starting from shell-derived CaCO₃, describing all the steps and synthesis routes proposed for the conversion procedure, with a special focus on the different species of marine shells used. We discussed the use of HA alone or in combination with other materials (natural and synthetic polymers), used to enhance the mechanical and biological properties.We summarized the types of devices obtained by marine-derived HA, including nanorods, particulates and scaffolds and we described their in vitro and in vivo behavior.The up-to-date literature was summarized in tables with a special focus on the in vitro and in vivo biological evaluation of such materials.In conclusion, composite biomaterials based on marine-derived biogenic HA are reported as potential candidates for synthetic bone substitutes highlighting their potential, limitations and future perspectives.     

Modification of hydroxyapatite (HA) powder by carboxymethyl chitosan (CMCS) for 3D printing bioceramic bone scaffolds

The poor mechanical properties of 3D printed HA bone scaffold is always a challenge in tissue engineering, to address this issue, carboxymethyl chitosan (CMCS) was proposed to modify HA bone scaffolds by a physical blending method in this research. A series of HA and HA/CMCS composite ceramic scaffolds were printed by using piezoelectric inkjet 3D printing technology, and their properties were investigated in terms of forming quality, structural morphology, mechanical properties, degradability, cytotoxicity, and cell adhesion growth. The results of forming quality and structural morphology show that with the increase of CMCS content, the forming quality of the samples deteriorated, the pore size and porosity increased. However, when the content of CMCS reached 5 wt%, obvious cracks appeared on the surface of the sample, and the forming quality was relatively poor. The mechanical testing results indicated the toughness of composites could be enhanced by incorporating CMCS into HA, which was attributed to the higher strength connections of the CMCS polymer network between HA particles and the stronger interaction between HA and CMCS molecules. FTIR spectra further revealed the strong hydrogen bonding interaction between CMCS and HA. Moreover, the degradation rate and mineralization ability of the sample increased with the content of CMCS, but the compressive strength during degradation increased with the CMCS content, indicating that incorporating CMCS into HA cannot only improve the mechanical property and biological activity of the scaffold but also makes up the defect of slow degradation of pure HA scaffold. Finally, the cytotoxicity, cell adhesion, and cell proliferation tests show that HA and HA/CMCS composite samples had good cytocompatibility, HA/CMCS sample with 3 wt% CMCS possessed the best bioactivity. In summary, HA/CMCS composite powder with 3 wt% CMCS content is the optimal matrix material for 3D printing bone scaffolds.     

Molecular dynamics simulation and experimental study of the bonding properties of polymer binders in 3D powder printed hydroxyapatite bioceramic bone scaffolds

Binder properties are a key factor affecting the quality of bone scaffolds produced using 3D powder printing. In this research, molecular dynamics simulation (MD) and experimental methods were applied to study the cohesive energy density, mechanical properties, bonding behavior, and surface morphology of three polymer binders (PVP, PAM, PVA) employed in the 3D fabrication of hydroxyapatite (HA) bone scaffolds. The bonding mechanisms of the three polymer binders were revealed by analyzing the interaction between the binders and the HA surface. The binding energies between the binders and HA are associated with the cohesive energy density and viscosity of each of the binders, which are attributed to functional groups in the binders. The mechanical properties determined experimentally for the bone scaffolds produced using each of the three polymer binders were in a different relative order than the engineering modulus of the binders and the interaction between the binders and HA calculated in simulations. This is a reflection of the mechanical properties of bone scaffolds being a comprehensive reflection of the basic materials and their bonding effect. Finally, SEM imaging indicated additional factors affecting the mechanical properties and degradation rate of the scaffolds. Conclusions from this work can be used to forecast the properties of three commonly used polymer binders and provide a theoretical basis for the choice of binders in the production of 3DP-fabricated bone scaffolds.     

Effects of Surface Modification on the Properties of Poly(lactide-co-glycolide) Composite Materials

HA/PLGA composites with and without APS-modification were successfully prepared via solution dispersion method. The mechanical test of composites was performed by the three-point-bending test and the micrographs of materials were observed using SEM. The results indicate that by surface modification, uniform HA particles without agglomeration were obtained. Furthermore, the bending strengths and moduli of APS-HA/PLGA composites are higher than those of unmodified composites, which both first increased and then significantly decreased with increasing the HA content. The biocompatibility results show that modified HA/PLGA composite are more favorable biomaterials for cell adhesion, differentiation and proliferation than unmodified composites.     

硅酸钙类骨水泥改性研究进展

硅酸钙类骨水泥材料具有良好的自固化性能，能够作为硬组织修复材料对缺损的骨和牙进行填充和修复，但是由于其力学性能不足、固化时间长等缺点限制了其在临床上的应用范围。该文主要综述了硅酸钙粉体的制备方法及硅酸钙类骨水泥的力学强度、凝结时间、可注射性、降解及生物相容性等，并提出今后的研究重点是利用各体系骨水泥间的性能互补关系，将硅酸钙类骨水泥与其他体系骨水泥进行交叉复合，有望获得综合性能优良的无机复合骨水泥。