柠檬酸改性聚乙烯醇制备可生物降解膜的研究

选择柠檬酸（CA）作为单体在聚乙烯醇（PVA）水溶液中制备柠檬酸改性的聚乙烯醇交联聚合物,并用红外光谱表征膜的结构：重点考察了反应时间和反应温度对柠檬酸改性聚乙烯醇键合度的影响;使用淀粉与聚乙烯醇交联聚合物共混,制备了柠檬酸改性聚乙烯醇（CA—SP）,并将其延流成膜,采用溶菌酶体外降解实验,测定CA—SP膜的降解性能,与柠檬酸键合量对生物降解的影响。测试了降解的CA—SP膜的力学性能考察。结果表明：柠檬酸的多羧基结构,能与PVA的羟基发生酯化,从而改性淀粉／聚乙烯醇（SP）;在60℃下,反应3h时,柠檬酸的键合量可达到最大,为3．92g/g。使用溶菌酶对其进行降解,通过降解的失重率测定,发现柠檬酸的键合量越高,膜降解性能越好。柠檬酸改性的SP膜几乎可以达到完全降解。     

锂离子电池聚合物正极材料研究进展

高储能的锂电池聚合物正极材料是近年来新型电化学能源研究发展的热点。本文综述了自由基聚合物、导电聚合物、有机多硫聚合物以及多骨架碳硫交联聚合物正极材料的结构、制备、导电机理和电化学性能。重点介绍了自由基聚合物氮氧结构的特点和快速充放电性能,导电聚合物的合成方法和掺杂机理,以及有机多硫聚合物和多骨架碳硫交联聚合物中—(S—S)n—键的高效储能特性和超高比容量性质。最后提出了解决聚合物材料容量的衰减和易降解性以保证稳定的循环性能以及完善合成及制备工艺是未来的研究重点。     

高热稳定性和可逆交联性质的含新型偶氮发色团电光聚合物的研究

制备了两种新型的分别含有以三苯胺为电子给体的偶氮类发色团作为特征活性官能团和3-呋喃甲酸及受保护的马来酰亚胺的可交联型聚合物体系．通过研究表明利用该制备方法，发色团在聚合物中的含量得到了极大的提高，分别达到32．1％（NLO1_P1）和44．4％（NLO1_P2）．该聚合物体系以“DielsAlder”[4＋2]环加成反应作为其交联特征，具有高温非交联、低温交联的特点，其过程与以往的热交联型聚合物相反，可解决传统电光交联聚合物中存在的热交联对极化效率影响的问题并用热失重分析法（TGA）和差示扫描量热法（DSC）分析了这一过程．此外DA交联型聚合物，不需要引入额外的助交联剂，克服了传统热交联聚合物分离难的问题，最大程度的保证了材料的纯度．     

溶剂在交联硅橡胶中无限稀释扩散系数测定

气相色谱法测定溶剂与聚合物材料之间的相互关系是一个快速、准确、方便的方法，为此利用气相色谱法测定了小分子溶剂在不同交联剂含量的交联硅橡胶中的无限稀释扩散系数，并研究了交联剂用量对无限稀释扩散系数的影响，这为研究交联硅橡胶特性提供了新方法。     

金属—橡胶硫化粘接复合体剥离破坏行为的研究

本文分析了对橡胶分子链特性、部分交联弹性聚合物材料的粘弹行为及金属──橡胶硫化粘接体剥离过程中聚合物分子链的应力分布状况和剥离破坏模型，认为粘着一滑动（Stick—slip）模型剥离破坏并非是橡胶类材料的固有特征，而是由于金属──橡胶硫化粘接过程中的分子取向交联和部分交联弹性材料多个凯尔文（Kelvin）模型粘弹行为的综合结果．同时指出单从剥离试验的结果难以表征金属——橡胶硫化粘接复合作的粘接效果．     

多孔聚磷酸钙生物陶瓷的研究与应用

本文阐述了聚磷酸钙的国内外研究现状,初步揭示了聚磷酸钙生物陶瓷（CPP）的生物相容性和降解特性。现有的研究表明,聚磷酸钙的聚合度和晶型不同,降解速率也不同,为生物陶瓷可控降解提供了新的途径。聚磷酸钙属直链状无机聚合物,具有不完全结晶性。聚磷酸钙材料在生物相容性、降解性和力学性方面的综合优势,使其在骨修复材料领域格外受到青睐。     

热可逆性共价键交联氯醇橡胶的制备和性质

以环戊二烯基钠（ＣＰＤ－Ｎａ）与氯醇橡胶（ＣＨＲ）反应，制得了含ＣＰＤ侧基和双环戊二烯交联的聚合物。研究了反应物基团配比、反应温度对凝胶化时间和交联聚合物得率的影响。结果表明，随ＣＰＤ－Ｎａ用量的增加和反应温度的升高，ＣＨＲ形成凝胶的时间缩短。测定了交联聚合物的热可逆转化行为，发现交联聚合物在高温下可发生逆Ｄｉｅｌｓ－Ａｌｄｅｒ反应。     

弹性体辐射交联与过氧化物交联的比较

正辐射技术可以方便地在材料中诱导产生自由基,从而在许多聚合物中导致生成交联键。这样,我们就可以对弹性体的特性进行有利改性。据报道,过氧化物交联与辐照结合可达到使用常规交联方法无法获得的性能。要理解利用电离辐射处理聚合物的现象,应解释辐射化学领域的一些基本概念。电离辐射作用下,聚合物会产生不同的化学过程,如交联、降解和生成低分子量产物。辐射化学(不仅仅是固体)的起点是了解分子水平的异质     

可生物降解聚苹果酸丁二醇酯弹性体的制备及表征

以苹果酸和1,4-丁二醇为单体通过熔融缩聚制备出来了一种新型的可生物降解弹性体材料——聚苹果酸丁二醇酯（PBM）,初步研究了材料的亲水性能和降解性能,并对材料的结构进行了初步表征。研究结果表明：PBM的聚集态结构为无定形态,透明柔软,玻璃化转变温度在0℃以下;通过调节合成单体的物质的量比,改变预聚物的后期固化时间,控制后期固化交联（反应）时间等手段,实现了降解性能可控,吸水率可调节的目标。     

全氟聚醚聚合物及其功能复合材料的研究进展

全氟聚醚（PFPE）聚合物具有极低的表面张力、低摩擦系数、优异的润滑性能和良好的疏水疏油性能，被广泛用作航空航天、核工业、真空、电子等领域的润滑材料以及合成功能复合材料的反应中间体。近年来，基于PFPE聚合物的含氟功能复合材料在一些新兴领域受到广泛关注。本文首先介绍了PFPE聚合物在润滑材料领域最新的研究进展，重点阐述了目前PFPE润滑剂在抗磨、防锈和PFPE基础油抗爬移方面存在的不足，并分析了其原因；其次概述了PFPE聚合物在功能涂层、含氟聚氨酯材料、氟橡胶以及类玻璃（Vitrimers）材料方面的研究进展和应用前景，并介绍了一些含氟功能复合材料的制备工艺；最后展望了PFPE聚合物未来的研究重点和发展趋势，旨在为拓宽PFPE聚合物的应用领域，开发高附加值的PFPE衍生产品提供思路。     

Barrier properties and abrasion resistance of biopolymer‐based coatings on biodegradable poly(lactic acid) films

Coated polylactic acid (PLA) films consisting of crosslinked‐chitosan/beeswax layer were prepared to improve barrier properties and abrasion resistance of the base substrate. The effect of crosslinking the chitosan layer on durability and barrier properties of the coatings was investigated. Crosslinked samples exhibited lower degree of swelling compared to uncrosslinked samples and 50% reduction in water vapor transmission rate (WVTR) compared to neat PLA films. The beeswax coating decreased the WVTR of chitosan‐coated PLA films significantly (by 100%). However, it had a marginal effect on the oxygen transmission rate. Water vapor transmission was less affected by abrasion than oxygen transmission for both uncrosslinked and crosslinked samples. The WVTR of crosslinked samples were retained even after being subjected to abrasion, whereas WVTR of uncrosslinked samples dropped by 50%. Results obtained using the Taber test method also show that the weight loss of crosslinked coatings are about 75% less than that of uncrosslinked samples and can withstand a greater number of cycles before rupture. These translucent‐coated films retained good barrier and mechanical properties along with providing improved abrasion resistance after crosslinking. This approach provides exciting new possibilities for expanding the use of biodegradable polymers in packaging applications. POLYM. ENG. SCI., 59:1874–1881, 2019. © 2019 Society of Plastics Engineers     

Development and long-term in vivo evaluation of a biodegradable urethane-doped polyester elastomer

We have recently reported upon the development of crosslinked urethane-doped polyester (CUPE) network elastomers, which was motivated by the desire to overcome the drawbacks presented by crosslinked network polyesters and biodegradable polyurethanes for soft tissue engineering applications. Although the effect of the isocyanate content and post-polymerization conditions on the material structure-property relationship was examined in detail, the ability of the diol component to modulate the material properties was only studied briefly. Herein, we present a detailed report on the development of CUPE polymers synthesized using diols 4, 6, 8, 10, or 12 methylene units in length in order to investigate what role the diol component plays on the resulting material's physical properties, and assess their long-term biological performance in vivo. An increase in the diol length was shown to affect the physical properties of the CUPE polymers primarily through lowered polymeric crosslinking densities and elevated material hydrophobicity. The use of longer chain diols resulted in CUPE polymers with increased molecular weights resulting in higher tensile strength and elasticity, while also increasing the material hydrophobicity to lower bulk swelling and prolong the polymer degradation rates. Although the number of methylene units largely affected the physical properties of CUPE, the choice of diol did not affect the overall polymer cell/tissue-compatibility both in vitro and in vivo. In conclusion, we have established the diol component as an important parameter in controlling the structure-property relationship of the polymer in addition to diisocyanate concentration and post-polymerization conditions. Expanding the family of CUPE polymers increases the choices of biodegradable elastomers for tissue engineering applications.     

Biodegradable Photo-Crosslinked Thin Polymer Networks Based on Vegetable Oil Hydroxy Fatty Acids

Novel crosslinked thin polymer networks based on vegetable oil hydroxy fatty acids (HFAs) were prepared by UV photopolymerization and their mechanical properties were evaluated. Two raw materials, castor oil and 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) were used as sources of mono- and di-HFAs, respectively. Poly(ethylene glycol) (PEG) diacrylate and poly(ε-caprolactone) diacrylate were synthesized and used as crosslinking agents to form crosslinked polymer networks by UV-initiated free-radical polymerization with acrylated castor oil or acrylated DOD. The synthesis of acrylate derivatives was confirmed using FT-IR and ¹H-NMR spectroscopic techniques. The composition of the reaction mixture and the type/length of crosslinking agent were changed to obtain crosslinked polymer networks with various mechanical properties. For polymers prepared from high molecular weight (20,000) PEG, a 58–60% of the initial weights decreased in 35 days in phosphate buffer solution (pH 7.2) containing lipase enzyme. These potentially biodegradable polymers based on vegetable oil HFAs can be used as eco-friendly materials for various applications to replace the existing petroleum-based polymers currently used.     

全生物降解高分子材料的发展现状

生物降解高分子材料因医药、医学、环境等方面的需求而迅速发展起来,在近几十年,世界先进国家非常重视该领域的研究和开发工作,并取得一些重要进展。在简要介绍生物降解高分子材料的降解过程后,着重对全生物降解高分子材料的发展现状作了综述,其中包括化学合成高分子和天然高分子的研究和开发,同时对生物降解高分子材料存在的问题及其将来发展趋势等方面进行了讨论。     

Oxygen transmission through highly crosslinked polymers

Highly crosslinked polymers of varying structure were produced by the reaction of poly(glycidyl acrylate) (PGA) and methacrylate (PGM) with a variety of anhydride crosslinking agents: chlorendic (CA), glutaric (GA), maleic (MeA), succinic (SA), and polyrnalonic (pMnA) anhydrides. Topology was also varied by the use of a diluent and a comonomer in the backbone chain. Oxygen permeation measurements were made on these polymers coated onto a polypropylene film substrate before crosslinking. The crosslinking process greatly reduced the O₂ permeability which, however, was dependent not only on the degree of crosslinking (yield of the crosslinking reaction), but also on the crosslink density, the chemical nature of the structural elements, and the topology of the polymer network. Thus the most impermeable coating (XPGA/CA) was made not from the stiffest and bulkiest components (PGM and CA), but by the reaction of the bulkiest anhydride (CA) with the more flexible polymer backbone chain (PGA). This is explained in terms of the need for chain flexibility to produce a crosslinked structure of optimum space filling character and network tightness.     

生物降解高分子材料的研究新进展

综述了生物降解高分子材料制备方法和降解机理的研究新进展 ,并讨论了结构、组成、形态和外界条件等因素对均聚物、共聚物和高分子共混物生物可降解性的影响 ,简述了生物降解高分子材料在生物医学、包装和农业领域的潜在应用。     

Biodegradable polymers. XI. Spectral,thermal, morphological,and biodegradability properties of environment‐friendly green plastics of soy protein modified with thiosemicarbazide

The demand for biodegradable polymers produced from renewable natural resources continues to grow as environmental concerns increase. Biodegradable plastics derived from agricultural feedstock are a new generation of materials capable of reducing the environmental impact in terms of energy consumption and greenhouse effect in specific applications to perform as traditional/conventional plastics when in use and are completely biodegradable within a composting cycle through the action of living/micro‐organisms. The objective of this study is to examine the potentiality and performance pattern of soy protein isolate (SPI) resin, modified with various concentrations of thiosemicarbazide (TSC), as a thermoplastic to substitute some conventional petroleum‐based plastics. The spectral, thermal, morphological properties and the biodegradability of the modified resin have been investigated. The spectral studies indicate that TSC is not crosslinked with the protein moiety; rather, it acts as a modifier. Thermogravimetric analysis of the modified material has been followed using a computer analysis method (LOTUS package) developed by us for assigning the degradation mechanism. A number of equations have been used to evaluate the kinetic parameters. The degradation mechanism has been ascertained on the basis of the kinetic parameters. It is expected that, this environment‐friendly, fully biodegradable and sustainable TSC‐modified SPI green plastic could be commercially used for making molded products. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3134–3142, 2007     

Non-isothermal degradation kinetics of virgin linear low density polyethylene (LLDPE) and biodegradable polymer blends

The thermal degradation kinetics of several polymers, including biodegradable blends were investigated in non-isothermal thermogravimetry using several analytical methods. Virgin linear low density polyethylene (LLDPE) and LLDPE blends with polystarch-N (PSN), a prodegradant starch additive material used in 20 and 40 wt%., were investigated to determine the degradation behaviour of such materials in pyrolysis conditions. The results were compared to those obtained with virgin low (LDPE) and high density polyethylene (HDPE). An analytical solution model was also developed to assess the two degradation steps of the biodegradable blends which enabled the assessment of the apparent activation energy (E_a) of each material in the blend on its own based on the initial and final degradation temperatures. It was observed that the thermal behaviour and E_a value didn’t change significantly with the increase of biodegradable prodegradant, which shows that biodegradable blends can be treated with similar conditions regardless of the content of the biodegradable masterbatch present in the blend.     

Synthesis, mechanical properties and chemical/solvent resistance of crosslinked poly(aryl-ether-ether-ketones) at high temperatures

A synthetic two-stage procedure was developed for the synthesis of moderately crosslinked polymers based on poly(aryl-ether-ether-ketone) (PEEK). Rigid crosslinks based on aromatic imines were synthetically introduced into PEEK polymer matrix resulting in PEEK materials with various degrees of crosslinking. Two specific crosslinked PEEK polymers (5% and 10% of ketone groups crosslinked) were characterized and studied in detail. Thermomechanical properties, as well as chemical/solvent resistance of these materials at high temperatures (175-280 °C) were investigated and compared to the original PEEK material (Victrex 151G). The introduction of rigid crosslinks was shown to disrupt crystallinity of PEEK very efficiently. Because tensile properties of PEEK depend on its crystallinity, we observed a decrease in properties such as Young's modulus and the ultimate elongation, the extent of which depended on the degree of crosslinking. We also observed an improvement in the elastomeric properties of the crosslinked materials, such as decrease in initial permanent set during high temperature cyclic tensile testing. Mechanical creep behavior at high temperature also improved for crosslinked polymers vs the original commercial Victrex 151G in terms of a reduced irreversible creep component. All crosslinked materials showed excellent resistance to hot oily, acidic and basic environments, as well as excellent thermal stability. Overall, we were able to synthesize “softer” materials that are more rubbery at high temperature than commercial thermoplastic Victrex 151G; these elastomer-like materials showed promising mechanical properties for high temperature applications in hot/corrosive environments.     

增塑剂用量对交联淀粉-聚己内酯共混材料性能的影响

将热塑性交联淀粉与聚已内酯熔融共混,制备了可生物降解材料,考察了各种条件对材料的影响。结果表明：增塑剂用量对材料的力学性能有明显的影响。拉伸强度下降、断裂伸长率上升;甘油与水相比,甘油对断裂伸长率的改善作用更明显;体系中增塑剂甘油含量的增加有助于提高材料的耐水性,但略微降低了材料的降解性能。