天然植物纤维增强塑料复合材料降解性能研究进展

近年来,天然植物纤维增强塑料复合材料的产出呈现出激增趋势。产量激增为其废弃物的及时处理带来了难题。材料的有效降解不仅能解决这一难题,也能促进该类复合材料产业的发展。本文介绍了植物纤维增强塑料复合材料的主要降解方法,并从光降解、热降解、化学剂降解、酶降解及微生物降解等方面对其降解性能的研究现状进行综述,提出了该类复合材料降解亟待解决的难题。     

竹纤维/聚丙烯复合材料界面相容性研究进展

竹纤维具有密度低、强度高、价格低和可再生等优点,是工程结构材料中的理想增强材料。以竹纤维增强聚丙烯是目前制备高性能聚丙烯复合材料的研究热点,也是可持续发展的重要方向之一。为得到高性能的复合材料,需要对竹纤维和聚丙烯基体界面进行处理。本文综述了改善竹纤维与聚丙烯基体界面相容性的三种方法,包括竹纤维的表面改性、聚丙烯基体的改性和添加第三组分,指出了三种方法的优缺点,并展望了提高竹纤维/聚丙烯复合材料界面相容性的研究方向。     

植物纤维/不饱和聚酯树脂复合材料的研究进展

综述了近年来以不饱和聚酯树脂为基体、各种植物纤维为增强体的复合材料的研究进展,包括麻纤维、木纤维、竹纤维和其他植物纤维,对不同种类的复合材料的力学性能、吸水性能、热性能等进行了简要说明,对碱处理、偶联剂处理等对复合材料性能的影响进行了阐述,同时对此类复合材料的开发前景进行展望。     

含液晶聚合物的原位复合材料中界面相容性的改善策略

综述了近年来含液晶聚合物的原位复合材料中增容技术的一些进展,主要了四种增容技术,即加入具有增容作用的第三组分;在分散相液晶聚合物的主链上引入与基体树脂主链中相同或相似的单元,酯交换反应和多元共混技术,简要描术字原位复合材料的发展趋势。     

共混方法对聚氯乙烯/聚丙撑碳酸酯相容性影响

本文分别用溶液法和熔融法制得聚氯乙烯（PVC）与聚丙撑碳酸酯（PPC）共混试样，用DSC证明PVC／PPC共混物不相容，但它们不相容的程度受分子量、共混比例等因素的影响，并根据玻璃化转变温度（Tg）计算出溶液共混试样PPC富相中PVC的重量百分含量。NBR／PPC弹性体作偶联剂对PVC／PPC共混体系具有较好的增容作用，共混物中PPC的用量及分子量对共混体系性能有一定的影响。     

关于植物纤维高值化利用课程教学实践与改革的探讨

植物纤维高值化利用是研究植物纤维原料,特别是纤维素、半纤维素、木质素三种天然高分子分离及其高值化加工利用的一门学科,是林产化工、制浆造纸、生物质能源等专业的一门重要基础课程。本文针对该课程的特点及教学改革进行了探讨,认为可采取以下措施:(1)教学内容设置核心知识,突出教学重点;(2)关注学科发展前沿,及时更新教学内容;(3)知识形象化促进理解,启发式教学启迪思维;(4)注意科学研究思维方式的传授,开展研讨专题讲座;(5)加强理论教学与实践的结合,改革考核方式,注重综合能力考查。     

聚合物锂离子电池界面相容性的研究进展

聚合物锂离子电池作为储能装置在电子产品中具有广泛的应用前景。电极/聚合物电解质(E/P)界面相容性是影响聚合物锂离子电池电导率、安全性、机械性能的重要影响因素之一。研究E/P界面的电化学反应及形成机理,是解决相容性问题的关键。本文综述了近年来有关聚合物锂离子电池E/P界面相容性及相关研究技术的进展,并对聚合物锂离子电池界面相容性的相关研究进行了展望。     

聚合物锂离子电池界面相容性的研究进展

聚合物锂离子电池作为储能装置在电子产品中具有广泛的应用前景。电极/聚合物电解质(E/P)界面相容性是影响聚合物锂离子电池电导率、安全性、机械性能的重要影响因素之一。研究E/P界面的电化学反应及形成机理,是解决相容性问题的关键。本文综述了近年来有关聚合物锂离子电池E/P界面相容性及相关研究技术的进展,并对聚合物锂离子电池界面相容性的相关研究进行了展望。     

钛酸酯偶联剂的结构对PVC/木质素复合材料性能的影响

本文采用钛酸酯系列偶联剂对造纸工业废渣──木质素磺酸盐进行处理，然后填充聚氯乙烯（PVC）制成复合材料．结果发现用钛酸酯类偶联剂处理的木质素磺酸盐，填充PVC体系，其拉伸强度随使用钛酸酯偶联剂不同，拉伸强度下降幅度不同，而冲击强度和伸长率都不同程度上升，尤以冲击强度的提高最为明显．     

嵌段共聚偶联剂对玻璃纤维增强聚丙烯界面粘结的影响

合成了苯乙烯与丁二烯及含C==C硅烷的嵌段共聚偶联剂。采用该嵌段共聚物对玻璃纤维进行了表面处理,通过单丝临界长度法测定了玻璃纤堆增强聚丙烯的界面剪切强度。结果表明：采用嵌段共聚偶联剂对玻璃纤维进行处理,可以有效地改善玻璃纤维增强聚丙烯的界面粘结,其界面改性效果优于普通小分子偶联剂;嵌段共聚偶联剂的分子结构对界面粘结有影响,采用适当的嵌段长度,可获得较好的界面粘结;在基体树脂中加入功能化聚丙烯。可改善复合体系的界面粘结;基体树脂分子链较长或流动性好、粘度低,有利于基体与歼堆的的界面粘结。     

Antimicrobial Properties of Plant Fibers

Healthcare-associated infections (HAI), or nosocomial infections, are a global health and economic problem in developed and developing countries, particularly for immunocompromised patients in their intensive care units (ICUs) and surgical site hospital areas. Recurrent pathogens in HAIs prevail over antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. For this reason, natural antibacterial mechanisms are a viable alternative for HAI treatment. Natural fibers can inhibit bacterial growth, which can be considered a great advantage in these applications. Moreover, these fibers have been reported to be biocompatible and biodegradable, essential features for biomedical materials to avoid complications due to infections and significant immune responses. Consequently, tissue engineering, medical textiles, orthopedics, and dental implants, as well as cosmetics, are fields currently expanding the use of plant fibers. In this review, we will discuss the source of natural fibers with antimicrobial properties, antimicrobial mechanisms, and their biomedical applications.     

钛酸酯偶联剂的合成及应用

本文叙述了单烷氧型、磷酸酯型和螯合型钛酸酯偶联剂的合成,以及它们在高分子材料中的作用和应用范围.     

Characterization of hdpe/ha Composites Treated with Titanate and Zirconate Coupling Agents

The development of new materials for bone substitution has been of great interest for the scientific community in the last years. High-density polyethylene (HDPE) and hydroxyapatite (HA) composites have been used in biomedical applications without any inflammatory response. However, the differences in nature of both materials have motivated the use of coupling agents to improve their interfacial interactions. In this work, the effects of adding three different commercial coupling agents (NZ12, Lica01, Lica12) to high-density polyethylene (HDPE)/hydroxyapatite (HA) composites were studied. Composites containing 20 parts per hundred (phr) of HA previously treated with the already mentioned coupling agents were characterized by mechanical tests and their morphologies were analyzed afterwards. Composites with 0.3 and 0.5 wt% of NZ12 unfolded an increase in their Young's modulus and tensile strength, as a consequence of an improved dispersion of the filler into the polymeric matrix. Analysis of the samples by XPS showed that the zirconate coupling agent interacted more with the HA, as reflected in the lower binding energies of the corresponding oxygen atoms, which agrees with their better performance from the mechanical point of view.     

Use of Aminosilane Coupling Agents in Cementitious Materials

The work presented in this paper has been focused on the evaluation of the influence of the addition of aminosilanes like γ-aminopropyl-triethoxysilane (3-AMPS) on physical and mechanical properties of fresh and hardened polymer modified cement mortars (PMCMs), which contained also mineral fillers like fumed silica and blast furnace slag. The role of the aminosilane in cementitious system was to produce surface modification and covalent bonding among different inorganic phases of inorganic matrix (cement, aggregate, fumed silica) and strong chemical interaction between inorganic matrix and organic (polymer) phase of the mortar. The strong chemical bonding of inorganic matrix and polymer phase transformed composite mortar into cementitious material with more like monolithic structure. Mortars with the addition of aminosilanes showed improved physical-mechanical properties like bending strength, adhesion to concrete, and lower dry-shrinkage.     

Compatibility mechanisms between EVA and complex impact heterophasic PP-EPx copolymers as a function of EP content

Compatibility mechanisms between EVA and complex heterophasic iPP-EPx copolymers have been studied as a function of EP content. Systematic studies were made in order to characterize the thermal, morphological and mechanical behavior, before and after blending a series of PP-EPx/EVA concentrations. Multiple melting, proportional to the EP content, was observed for the neat copolymers and an explanation was given for its evolution in terms of rejection-like secondary crystallization. After blending with EVA, the generation of a single T_g was taken as an indication of compatibility between both polymers. A morphological transition toward compatibility was first determined at 20 wt.% EVA which was in correlation with a morphological change from isolated spherical domains to interconnected voids. A second morphological transition from interconnected voids to fibrous crystals was observed above 40 wt.% EVA. This last transition marked the beginning of compatibility. Overall, the evolution of blends was explained in terms of the nature of the complex heterophasic copolymers. Tensile mechanical studies were also consistent with morphological changes. Increases in the x content in EPx and in EVA concentration worked in favor of impact resistance.     

PBT／PET共混体系非晶区的相容性

利用ＰＢＴ、ＰＥＴ的特性参数，通过不同组份比ＰＢＴ／ＰＥＴ共混体系的混合自由能△Ｇｍ，从理论上预测其相容性。在一定的条件下△Ｇｍ＜０，ＰＢＴ、ＰＥＴ可以相容。对不同组份比共混体系的玻璃化转变过程从分子链段运动的角度进行分析。     

Pd@sPS-NMe_2/AC纳米催化剂制备及在偶联反应中的应用

用胺基功能化间规聚苯乙烯(sPS-NMe_2)与活性炭(AC)分别利用混合沉降法(MP)、混合挥发法(MV)及直接聚合法(DP)制备了sPS-NMe_2/AC复合载体.sPS-NMe_2/AC吸附还原PdCl_2后获得Pd@sPS-NMe_2/AC催化剂.采用扫描电镜和透射电镜对sPS-NMe_2/AC和Pd@sPS-NMe_2/AC形貌进行了分析,考察了sPS-NMe_2/AC复合方法、用量对其形貌、负载Pd金属的影响,发现MV法获得的sPS-NMe_2/AC在其质量比大于1/3时sPS-NMe_2可均匀覆盖AC, Pd纳米粒子为3 nm左右,均匀稳定分散.该催化剂在"借氢"、 Suzuki-Miyaura、 Heck和Sonogashira偶联反应中表现出了优异的催化性能.