一种新的可生物降解聚碳酸酯的合成与表征

以天然氨基酸(L-酪氨酸)为原料合成环二肽,以环二肽为单体用光气法合成了属于拟聚氨基酸的聚碳酸酯,该聚合物的结构特点为主链肽键与非肽键重复排列,其主链结构中既有水解键又有酶解键。差示扫描量热法、热重分析法和凝胶渗透色谱法的分析结果显示,聚合物的玻璃化转变温度低于100℃,热降解温度在300℃以上,聚合物多分散度为1.338。X射线衍射结果表明,合成的聚合物为无定形物。     

新型无毒可生物降解氨基酸衍生环氧树脂的合成与表征

用天然氨基酸为起始材料,合成了一种具有双酚羟基官能团的环肽,并以此环肽为联酚合成了主链包含酰胺键的可生物降解环氧树脂。用FT-IR与NMR表征了合成氨基酸衍生环肽与对应环氧树脂的化学结构,结果表明合成了预期结构。用盐酸丙酮法测定了合成环氧树脂的环氧值。     

可生物降解塑料的降解性能研究进展

介绍了可生物降解塑料的降解机理及一些典型可生物降解材料的降解过程,分析了影响降解的内外因素,列举了塑料降解性能的检测方法以及相关国内外检测标准等。     

一种可生物降解水合物动力学抑制剂的研究

目前用于天然气水合物防治的工业动力学抑制剂主要是水溶性聚合物,如聚乙烯基吡咯烷酮（PVP）、聚乙烯基己内酰胺（PVCap）、Gaffix VC-713等,然而生物降解性低限制了其工业应用。因此,开发环保型的抑制剂具有重要意义。实验采用易生物降解的海藻酸钠与PVCap的单体接枝共聚,合成一类新型水合物动力学抑制剂NaAlg-g-PVCap,结合最大过冷度及耗气量评价了新型抑制剂在水合物生成过程中的抑制性能,并通过BOD₅/COD值评价了新型抑制剂的生物降解性。结果表明低剂量[0.25%（质量）]下NaAlg-g-PVCap的最大耐受过冷度优于PVP K90,但低于PVCap,且随着添加剂量增大而微弱降低;在其最大耐受过冷度以下（ΔT_sub=5℃）,NaAlg-g-PVCap表现出较好的水合物成核和生长抑制作用,其体系水合物初始生长速率值约只为纯水体系的 1/10,也远高于PVP体系,且总耗气量相比纯水及PVP体系减少了60%以上,与PVCap体系接近,但随着过冷度增大,NaAlg-g-PVCap成核抑制作用下降明显,这可能是共聚物中两部分共同作用的结果;同时,NaAlg-g-PVCap相比PVCap其生物降解性提高了26%, 倾向于易降解。说明PVCap与NaAlg共聚后优化了整体的性能,表现出较好的水合物抑制性能和生物降解性。     

聚酯型可生物降解弹性体的表征及其降解

用丙三醇和癸二酸通过熔融共缩聚反应合成了具有一定热塑性、可生物降解的弹性体（tp-PGS）,并对其结构进行了表征,同时讨论了该弹性体的力学性能、亲水性能和降解性能。结果表明,tp-PGS属于一种交联网络型聚酯,具有以非晶相为软区、晶相为硬区的微观相分离结构。tp-PGS具有一定程度的热塑性,可模压成型。tp-PGS分子结构中所具有的羟基和酯基赋予其良好的生物降解性能。     

可生物降解材料降解性的研究进展

阐述了生物降解材料的降解机理及评价方法,综述了影响材料生物降解性的主要因素,包括材料的组成、结构、结晶状态,环境温度、湿度,pH值以及土壤成分等,指出了降解材料当前存在的主要问题,并对其发展前景进行了展望。     

慢速可生物降解有机物水解数学模型的研究进展

慢速可生物降解有机物(Xs)是城市污水和工业废水中有机物的主要组成部分,其水解速率是影响营养物去除的关键因素.阐述了Xs对(解的不同机理模型,介绍了不同的水解动力学模型的发展及应用,并对文献报道的动力学参数进行了总结和比较,最后提出Xs水解模型的研究趋势.     

一种新型可生物降解聚酯压敏胶的制备与性能

以丁二酸、己二酸、1,3丙-二醇、1,4丁-二醇为单体,C-94为催化剂,丙三醇为交联剂,制备了一种新型的、可生物降解的四元无规共聚酯压敏胶,使用核磁共振波谱仪测定了共聚酯中各单元的组成比例,并对其黏弹性、初黏性、持黏性、180°剥离强度等进行了表征,考察了交联剂用量对压敏胶性能的影响。实验结果表明,丙三醇质量分数为0.6%时,压敏胶性能较佳。     

影响可生物降解包装材料降解性能的内外部因素

综合分析了近10年来国内外在有效降低日用化学品包装废弃物对环境造成的污染方面的研究进展,从生物可降解高分子材料的内外部因素及外加干扰诸因素进行了剖析和归纳,得出了有益的结论.     

一种表面活性剂对活性污泥的影响及其可生物降解性的测试方法

以月桂醇聚醚硫酸酯钠(AES)、月桂醇聚醚硫酸酯铵(AESA)为例：通过污泥耗氧速率的变化了解表面活性剂对活性污泥的抑制情况;用磁力搅拌表面曝气法代替震荡培养法测试了城镇污水处理厂的活性污泥对表面活性剂的生物降解能力;用污泥负荷表征表面活性剂的初级生物降解速率,便于计算用活性污泥法处理表面活性剂至其起泡性能消失所需的时间。实验结果表明,AES、AESA浓度≥200 mg·L^-1时对活性污泥中部分微生物有抑制作用。当AES、AESA浓度≤100 mg·L^-1时,用城镇污水处理厂的活性污泥好氧处理的初级生物降解速率分别为0.06 kg AES.(kg MLSS·d)^-1、0.06 kg AESA.(kg MLSS·d)^-1;用活性污泥法好氧处理20小时后的COD_Cr去除率分别为75.7%、79.9%;AESA的可生物降解性优于AES。     

碱性溶液中在阴极上电催化降解木质素的研究

在常温常压下,用电沉积法制备的Ti/SnO_2-Sb2O3/α-PbO_2/β-PbO_2电极和钛、铁或锡阴极构成两电极体系,电催化降解芦苇木质素。考察电流密度、木质素浓度、温度和反应时间对降解产率的影响。结果表明,电催化降解芦苇木质素的主要产物为酚类,芳烃、芳香酯(如愈创木酚、丁香酚),当电流密度10～20 mA/cm²,木质素浓度40 g/L,温度35℃或45℃,电解时间5 h,分别使用Sn、Fe和Ti阴极下,苯酚、芳香酯和芳香烃的产率分别达到2. 31,0. 43,0. 98 g/kg。     

Comparative degradation of pultruded E‐glass/vinylester in deionized water,alkaline solution,and concrete leachate solution

The use of E‐glass/vinylester composites, fabricated by processes such as resin infusion and pultrusion involving low‐moderate temperature cure regimes, in civil infrastructure applications is increasing. A major consideration in these applications is long‐term durability in the presence of aqueous solutions ranging from water to alkaline environments such as would be seen from pore water of concrete in the case of a reinforcing bar in concrete, or from an alkaline rich concrete leachate due to water migrating through porous concrete to the surface of a composite overlay. This study characterizes mass uptake, tensile, and interlaminar shear response of a pultruded E‐glass/vinylester immersed in deionized water, alkali solution, and concrete leachate solution for periods up to 75 weeks. The high pH solutions are seen to cause a greater degree of irreversible damage at the resin, interface, and fiber levels. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1405–1414, 2006     

Development and evaluation of a novel pH indicator biodegradable film based on cassava starch

A pH indicator film based on cassava starch plasticized with sucrose and inverted sugar and incorporated with grape and spinach extracts as pH indicator sources (anthocyanin and chlorophyll) has been developed, and its packaging properties have been assessed. A second‐order central composite design (2²) with three central points and four star points was used to evaluate the mechanical properties (tensile strength, tensile strength at break, and elongation at break percentage), moisture barrier, and microstructure of the films, and its potential as a pH indicator packaging. The films were prepared by the casting technique and conditioned under controlled conditions (75% relative humidity and 23°C), at least 4 days before the analyses. The materials were exposed to different pH solutions (0, 2, 7, 10, and 14) and their color parameters (L*, a*, b*, and haze) were measured by transmittance. Grape and spinach extracts have affected the material characterization. Film properties (mechanical properties and moisture barrier) were strongly influenced by extract concentration presenting lower results than for the control. Films containing a higher concentration of grape extract presented a greater color change at different pH's suggesting that anthocyanins are more effective as pH indicators than chlorophyll or the mixture of both extracts. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of biodegradable amphiphilic thermo‐responsive multiblock polycarbonate and its self‐aggregation behavior in aqueous solution

Amphiphilic thermo‐responsive multiblock polycarbonates consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) were facilely synthesized using triphosgene as coupling agent. The structures and molecular characteristics of the polycarbonates were confirmed by ¹H‐NMR, FT‐IR and Gel permeation chromatography (GPC). The crystallization behavior and thermal properties of the polycarbonates were studied using X‐ray diffraction (XRD), Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Surface tension measurements confirmed that the critical micelles concentration of polymeric micelles were concentration ranges, which varied from about 2–70 mg/L to 5–40 mg/L with increasing PEO/PPO composition ratio from 0.8 to 1. Dynamic light scattering (DLS) experiments showed bimodal size distributions, the aggregates size increased with increasing the concentration of the polycarbonates aqueous solutions. The size of the aggregates acquired from TEM was smaller than that from DLS owing to the fact that TEM gave size of the aggregates in dry state rather than the hydrodynamic diameter. The degradation process revealed that the degradation rate of the aggregates could be accelerated with an increase in temperature. Moreover, the more the polycarbonate was hydrophilic, the faster was its degradation. Rheological measurements suggested that these multiblock polycarbonates were thermo‐responsive and by regulating the PEO/PPO composition ratio they could form a gel at 37°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Electropolymerization of phenol on a vitreous carbon electrode in alkaline aqueous solution at different temperatures

Electrochemical oxidation of phenol in basic aqueous solution has been studied on a vitreous carbon electrode at different temperatures in the range of 25-85 °C by cyclic voltammetry and chronoamperometry techniques. The electrochemical oxidation of phenol led to a complete deactivation of the electrode, whatever the temperature used, as a result of the deposition of an adhesive and insulating polymeric film. The electrochemical activity of the electrode was progressively restored by repeated potential scans in the range of water stability only when conducted at high temperatures; electrode reactivation was explained by an increase in the polymeric film permeability for both electrons (electron tunneling) and phenol molecules (diffusion). Chronoamperometric measurements carried out in the potential region of water stability have shown that electrode passivation was reduced or prevented at high temperatures. For chronoamperometry performed at the onset of oxygen evolution, the electrode remained active even at low temperatures because the discharge of water involved the production of hydroxyl radicals that destructively oxidized the polymeric film. The effect of temperature on electrode reactivation was determined by the measurement of current at an electrolysis time of 300 s; an increase of the temperature from 25 to 85 °C amplified the current from 0.212 to 5.373 mA.     

新型可生物降解弹性体的制备与性能

以聚乙二醇(PEG)和柠檬酸(CA)为单体,通过熔融缩聚制备了新型的可生物降解弹性体聚柠檬酸聚乙二醇〔poly(PEG-co-CA),PEC〕,并通过改变后期交联时间得到了一系列透明柔软的弹性体。用傅里叶变换红外光谱、X射线衍射仪及差示扫描量热仪对PEC进行了初步表征,表明产物在室温下为无定形态,且玻璃化转变温度都在0℃以下;力学性能测试表明所得材料的弹性模量为0.251.91 MPa,扯断伸长率为239.4%1 505.5%;在37℃和pH值为7.4的磷酸缓冲溶液中进行了体外降解实验,结果表明该弹性体为一种降解较快的材料(浸泡80 h后所有试样的降解都超过60%)。同时发现其力学性能、吸水性能和降解性能可通过改变后期交联时间加以调节。     

Synthesis and evaluation of novel injectable and biodegradable polyglycolide‐based composites

Novel 3‐arm methacrylate‐endcapped biodegradable polyglycolide prepolymer was synthesized and characterized. Injectable and in situ curable composites formulated with the liquid prepolymer and bioabsorbable β‐tricalcium phosphate were prepared. The pastelike composites were cured at room temperature using a redox‐initiation system. The initial compressive strengths (CSs), curing time, exotherm, and degree of conversion of the cured composites were determined. The composites showed initial yield CS ranging from 20.1 to 92.3 MPa, modulus from 0.73 to 5.65GPa, ultimate strength from 119.9 to 310.5 MPa, and toughness from 630 to 3930 N mm. Increasing filler content increased yield strength and modulus but decreased ultimate strength and toughness. Diametral tensile strength test showed the same trend as did CS test. Increasing filler content also increased curing time but decreased exotherm and degree of conversion. During the course of degradation, all the materials showed a significant burst degradation behavior within 24 h, followed by a significant increase in strength between Day 1 and Day 3, and then continuous degradation until no strength was detected. The composites with higher filler content retained their strengths longer but those with lower filler contents lost their strengths in 45 or 60 days. The degradation rate is filler‐content dependent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2977–2984, 2007     

纯铝在两种不同类型缓蚀剂的碱性溶液中的电化学行为研究

采用集气实验、极化曲线方法研究纯铝在4 mol/L KOH溶液中的电化学行为,溶液中分别添加碱土金属离子与EDTA、ZnO与DE后,实验结果表明铝在含0.02 mol/L EDTA和饱和Ca(OH)2、Sr(OH)2溶液与0.2 mol/L ZnO与0.3 mL/L DE溶液均具有最小的腐蚀速率。EDAX分析表明碱土金属离子与EDTA没有参与到铝表面氧化膜的组成中,说明该缓蚀剂是通过吸附在铝表面起作用的,它们是界面型缓蚀剂;而在含ZnO与DE溶液中,由于氧化锌被还原成锌,沉积在铝表面上,从而减少了析氢反应速率,属于成相型缓蚀剂。