Enzymatic degradation of poly([R,S] β-hydroxybutyrate)

The synthetic analogue of a bacterially produced polyester, poly(-hydroxybutyrate) (PHB) was synthesized from racemic -butyrolactone using anin situ trimethyl aluminum-water catalyst. The polymer was fractionated into samples differing in molecular weight and isotactic diad content. The latter was closely related to degree of crystallinity. The biodegradation of these fractions were examined by monitoring mass loss over time in the presence of anAlcaligenes faecalis T1 extracellular bacterial poly(-hydroxybutyrate) depolymerase. The fraction with high isotactic diad tacticity content showed little or no degradation over a 50 hour incubation period, whereas the fraction of intermediate isotactic diad content degraded in a continuous steady fashion at a rate that was less than that for bacterial PHB. The low isotactic diad fraction underwent a rapid initial degradation, followed by no further mass loss. The presence of stereoblocks in the polymer structure of the various fractions was an influence on the degree of susceptibility towards degradation and is related to sample crystallinity.     

溶济萃取法处理含硫酸及硫酸盐的废水

采用溶剂萃取法处理含硫酸及硫酸盐的工业废水，主产优质农用硫酸钾，副产氯化铵和氮钾复合肥，整个工艺过程基本无三废排放，实现了对该废水的综合有效治理。     

用硫酸渣制备铁基颜料铁黄

以硫酸渣为原料，用黄铁矿粉作还原剂，采用湿式空气氧化法制备铁基颜料铁黄。试验得出的适宜工艺条件为：Fe^2 浓度0．25—0．40mol/L，氧化温度70℃，用氢氧化钠或氨水调节反应液的pH，氧化过程溶液的pH控制在3—4。依照该工艺制得的铁基颜料铁黄，其各项指标符合HG／T2249—91标准。     

絮凝法分离谷氨酸菌体的研究

采用絮凝法对味精发酵生产过程中发酵液中的菌体进行研究，得到无机凝聚剂与高分子絮凝剂复合配比使用是发酵液去除菌体的有效办法。对复合用药除菌后的谷氨酸发酵液和原谷氨酸发酵液进行谷氨酸回收的比较，谷氨酸的回收率提高了8．8％。     

环己烷氧化废碱液的回收利用

介绍了一种从环己烷氧化废碱液中回收高价值有机酸的新方法。用氢氧化钠碱熔处理废碱液中的羟基己酸及其聚合物，可使废碱液中己二酸的质量分数由3．18％提高到8．74％，且环境效益和经济效益显著。     

Starch, Poly(lactic acid), and Poly(vinyl alcohol) Blends

Research on biodegradable materials has been stimulated due to concern regarding the persistence of plastic wastes. Blending starch with poly(lactic acid) (PLA) is one of the most promising efforts because starch is an abundant and cheap biopolymer and PLA is biodegradable with good mechanical properties. Poly(vinyl alcohol) (PVOH) contains unhydrolytic residual groups of poly(vinyl acetate) and also has good compatibility with starch. It was added to a starch and PLA blend (50:50, w/w) to enhance compatibility and improve mechanical properties. PVOH (M_W 6,000) at 10%, 20%, 30%, 40%, 50% (by weight) based on the total weight of starch and PLA, and 30% PVOH at various molecular weights (M_W 6,000, 25,000, 78,000, and 125,000 dalton) were added to starch/PLA blends. PVOH interacted with starch. At proportions greater than 30%, PVOH form a continuous phase with starch. Tensile strength of the starch/PLA blends increased as PVOH concentration increased up to 40% and decreased as PVOH molecular weight increased. The increasing molecular weight of PVOH slightly affected water absorption, but increasing PVOH concentration to 40% or 50% increased water absorption. Effects of moisture content on the starch/PLA/PVOH blend also were explored. The blend containing gelatinized starch had higher tensile strength. However, gelatinized starch also resulted in increased water absorption.     

废水中甲酸萃取回收的研究

以ＺＹＭ混合溶剂为萃取剂，以含４．５％的甲酸的废水进行萃取试验，结果表明，ＺＹＭ具有良好的热稳定性和再生性，对废水中的甲酸有较高的萃取率。采用本萃取技术，不但具有显著的环境效益，而且还可回收甲酸，获得较好的经济效益。     

Thermal and mechanical properties of poly(lactic Acid) and poly(ethylene/butylene Succinate) blends

In this study, blends of poly (lactic acid) (PLA) with poly(ethylene/butylene succinate) (Bionolle) have been investigated for their thermal and mechanical properties as a function of the concentration of Bionolle. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and tensile tests were used to characterize the blends. From the results of the DMA and DSC, it was found that this blend system was not miscible within the compositions studied. DSC results showed that adding Bionolle aids in crystallization of PLA. It was observed that increasing the Bionolle concentration led to a slight increase in the strain-at-break of the blends but a decrease in the Young’s modulus and ultimate tensile strength. Biaxially oriented films showed an increase in tensile strength, modulus, and strain-at-break.     

Synthesis of poly(hydroxyalkanoate) from hydrolyzed linseed oil

Pseudomonas putida was grown on a mixture of long-chain fatty acids obtained by hydrolysis of linseed oil. A poly(3-hydroxyalkanoate) containing 51.2% of unsaturated monomers was obtained. A considerable percentage (13.6%) was constituted by C₁₄ and C₁₆ monomers containing three double-bonds in the side chains. The polymer showed a high tendency to crosslink when it was kept in presence of air. In the crosslinked polymer no polyunsaturated monomers could be detected.