熔融聚合法合成生物材料聚(乳酸-谷氨酸)

以外消旋乳酸(D,L-LA)为单体,与L-谷氨酸(L-Glu)直接熔融聚合,合成了生物降解材料聚(乳酸-谷氨酸)共聚物.用特性粘数[η]、FTIR、1H NMR、GPC、DSC、XRD等手段进行系统表征,探讨了催化剂种类和用量、熔融聚合反应时间、反应温度以及不同投料比对聚合物合成的影响.在单体乳酸和谷氨酸投料物质的量比为98:2、150℃、70Pa、催化荆SnCl2的用量0.7%(质量分数)的条件下熔融聚合8h,聚合物重均相对分子质量(Mw)可达6400.随着谷氨酸投料量的增加,共聚物重均相对分子质量逐渐减小,Tg均低于直接熔融合成的聚外消旋乳酸,且共聚物均为无定形态.     

聚谷氨酸苄酯的化学改性研究进展

聚谷氨酸苄酯是一种新型的生物降解高分子材料,但由于其疏水性,降解周期及速度难以控制, 使其应用受到一定的限制,因此其改性研究具有重要的意义.综述了聚谷氨酸苄酯的共聚改性和侧基改性方法研究进展.     

N-月桂酰某谷氧酸添加剂在菜籽油中的摩擦学性能

传统的润滑油添加剂在低毒性、低污染和可生物降解方面不合环保要求.以月桂酰氯与谷氨酸在碱性溶液中反应,在脂肪酸分子中引入氮,合成了一种新型的润滑添加剂--N-月桂酰基谷氨酸,并用红外光谱对其结构进行了表征.通过四球机考察了它在菜籽油中的摩擦学性能,分析和研究了其添加含量和载荷对菜籽油摩擦学性能的影响.用扫描电子显微镜(SEM)对钢球表面的磨斑形貌进行了分析.结果表明:添加剂含量在1.5%内承载力、烧结负荷为最大;在0.5%内抗磨性最好.该添加剂在菜籽油中具有良好的极压性能和抗磨减摩性能.     

N-月桂酰基谷氨酸添加剂在菜籽油中的摩擦学性能

传统的润滑油添加剂在低毒性、低污染和可生物降解方面不合环保要求。以月桂酰氯与谷氨酸在碱性溶液中反应,在脂肪酸分子中引入氮,合成了一种新型的润滑添加剂——N-月桂酰基谷氨酸,并用红外光谱对其结构进行了表征。通过四球机考察了它在菜籽油中的摩擦学性能,分析和研究了其添加含量和载荷对菜籽油摩擦学性能的影响。用扫描电子显微镜（SEM）对钢球表面的磨斑形貌进行了分析。结果表明：添加剂含量在1．5％内承载力、烧结负荷为最大;在0．5％内抗磨性最好。该添加剂在菜籽油中具有良好的极压性能和抗磨减摩性能。     

受控堆肥生物降解法测定全生物降解塑料(PBS)性能

依据GB/T 19277-2003/ISO 14855:1999,对降解塑料聚丁二酸丁二醇酯(PBS)、丁二酸对苯二甲酸丁二醇共聚酯(PBST)进行堆肥化条件下生物降解能力的测定.试验结果,用此方法评价塑料生物降解性能是可行的.PBS、PBST具有良好的生物降解性.建立了高分子材料测定方法的操作系统.     

聚L-谷氨酸酯手性膜制备及其拆分对羟基苯甘氨酸

采用N-羧基内酸酐合成法,分别合成了不同分子量的聚L-谷氨酸甲酯、聚L-谷氨酸乙酯以及聚L-谷氨酸苄酯.将聚L-谷氨酸甲酯、聚L-谷氨酸乙酯以及聚L-谷氨酸苄酯制备成手性固膜,利用扫描电镜表征其结构.研究了不同分子量的聚L-谷氨酸酯、渗析溶剂中不同乙腈含量、原料液浓度、渗析时间、温度等对拆分对羟基苯甘氨酸外消旋体的影响.在优选的实验条件下,这些膜对对羟基苯甘氨酸的手性拆分的e.e.值可达45%以上,且聚L-谷氨酸甲酯聚L-谷氨酸乙酯聚L-谷氨酸苄酯.该研究为对羟基苯甘氨酸外消旋体的分离制备,提供了新的研究途径.     

聚乳酸类可生物降解材料在缓控释药物制剂中的应用

综述了用聚乳酸类可生物降解型高分子材料制备缓控释药物载体的研究现状.分别介绍了该类材料在微粒给药载体、凝胶制剂、缓释支架和埋植制剂的应用及其制备方法.阐述了目前聚乳酸类生物降解材料在缓控释药物制剂中的主要问题,展望了其发展前景.     

生物降解包装塑料研究进展

生物降解包装塑料是一种绿色包装塑料,生物降解法是一种很好解决废弃包装塑料的新方法.介绍了生物降解包装塑料的种类,分析了生物降解包装塑料的机理,综述了生物降解包装塑料的研究进展,指出了生物降解包装塑料的发展趋势.     

新型生物降解交联剂的制备及其在壳聚糖交联膜中的应用

本文用聚乙二醇和丙交酯在辛酸亚锡的催化作用下合成了可降解的二羟基中间体,再与2,4-甲苯二异氰酸酯(2,4-TDI)反应,合成了异氰酸酯基封端的一系列生物降解型交联剂.并且对中间体和交联剂进行了 FTIR分析表征.应用交联剂对壳聚糖膜材料进行交联,并对交联材料进行了吸水率,表面接触角及力学性能的测定,结果表明新型生物降解交联剂的运用不仪改善了材料吸水性,也提高了材料的力学性能.     

食品包装淀粉基生物降解薄膜阻氧性研究

本文综述了国内外食品包装用淀粉基生物降解薄膜的研究进展,讨论了目前开发食品包装用淀粉基生物降解薄膜阻氧性能检测方法的必要性和紧迫性。     

十二烷基肌氨酸钠对模拟混凝土孔隙液中钢筋的缓蚀作用

应用极化曲线法和电化学阻抗技术,考察了十二烷基肌氨酸钠对模拟混凝土孔隙液中钢筋的缓蚀作用.结果表明,十二烷基肌氨酸钠对在含氯离子的模拟混凝土孔隙液中的钢筋有良好的缓蚀效果.极化曲线和电化学阻抗谱的测试结果一致证实十二烷基肌氨酸钠的加入量为100mg/L时,对含0.6mol/L NaCl的模拟混凝土孔隙液中钢筋的缓蚀效果最好.     

HECA/聚己内酯-环氧丙烷共混膜的生物降解研究

研究了羟乙基纤维素醋酸酯与己内酯－环氧丙烷共聚物共混物膜的生物降解过程,发现共混物膜的生物降解性能与其组成密切相关。共混膜的降解速率随着已内酯－环氧丙烷共聚物含量的增加而加快。在降解过程中,分了量较小的部分首先开始降解,而且降解的速度较快。分子量高的部分降解较慢,控制着整个共混膜的降解速率。     

Biodegradation of phenol by Pseudomonas putida immobilized in polyvinyl alcohol (PVA) gel

Batch experiments were carried out to evaluate the biodegradation of phenol by Pseudomonas putida immobilized in polyvinyl alcohol (PVA) gel pellets in a bubble column bioreactor at different conditions. The bacteria were activated and gradually acclimatized to high concentrations of phenol of up to 300 mg/l. The experimental results indicated that the biodegradation capabilities of P. putida are highly affected by temperature, pH, initial phenol concentration and the abundance of the biomass. The biodegradation rate is optimized at 30 degrees C, a pH of 7 and phenol concentration of 75 mg/l. Higher phenol concentrations inhibited the biomass and reduced the biodegradation rate. At high phenol concentration, the PVA particle size was found to have negligible effect on the biodegradation rate. However, for low concentrations, the biodegradation rate increased slightly with decreasing particle size. Other contaminants such heavy metals and sulfates showed no effect on the biodegradation process. Modeling of the biodegradation of phenol indicated that the Haldane inhibitory model gave better fit of the experimental data than the Monod model, which ignores the inhibitory effects of phenol.     

Biodegradation of fenoxaprop-p-ethyl by bacteria isolated from sludge

A mixed bacterial population was isolated using enrichment in a basal medium containing increasing amounts of fenoxaprop-p-ethyl as a sole carbon source from sludge that had been exposed to fenoxaprop-p-ethyl production wastewater for about 2 years. Eight kinds of isolates could utilize fenoxaprop-p-ethyl, but only one was identified belonging to genus Alcaligenes, named Alcaligenes sp. H. In pure culture, there was 45.8, 66.0 and 69.5% loss of fenoxaprop-p-ethyl (initial concentration: 100, 50, 25 ppm, respectively) as the sole carbon source with biodegradation by Alcaligenes sp. H and fenoxaprop-p-ethyl degradation kinetics obeyed the first-order kinetics, the same as the fenoxaprop-p-ethyl biodegradation kinetics in soil. At least five degradation products of fenoxaprop-p-ethyl biodegradation by Alcaligenes sp. H and two degradation products of fenoxaprop-p-ethyl biodegradation by Huv separated by HPTLC. It is possible that the fenoxaprop-p-ethyl biodegradation by Alcaligenes sp. H includes the same pathway as that by Huv comparing with the Rf.     

Mathematical model of the non-steady-state adsorption and biodegradation capacities of BAC filters

This research was focused on developing a non-steady-state numerical model to differentiate the adsorption and biodegradation quantities of a biological activated carbon (BAC) column. The mechanisms considered in this model included adsorption, biodegradation, convection and diffusion. Simulations were performed to evaluate the effects of some parameters such as specific biodegradation rates and diffusivities on adsorption and biodegradation performances for the removal of dissolved organic matter from water. The results show that the developed model can predict the experimental data well. The biofilm developed around the BAC granules can hinder the mass transfer of the substrate onto the GAC surface, and the adsorption process will be restricted by the biofilm thickness. Although increasing the specific biodegradation rate can increase the performance of biodegradation, the adsorption efficiency will be decreased by lowering the boundary concentration in the interface of GAC. On the contrary, increasing the diffusivity can increase both the adsorption and biodegradation efficiencies simultaneously; so that the overall removal efficiency can be promoted through the improvement of mass transfer.     

Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium

The biodegradation of a hazardous waste (bilge waste), a fuel oil-type complex residue from normal ship operations, was studied in a batch bioreactor using a microbial consortium in seawater medium. Experiments with initial concentrations of 0.18 and 0.53% (v/v) of bilge waste were carried out. In order to study the biodegradation kinetics, the mass of n-alkanes, resolved hydrocarbons and unresolved complex mixture (UCM) hydrocarbons were assessed by gas chromatography (GC). Emulsification was detected in both experiments, possibly linked to the n-alkanes depletion, with differences in emulsification start times and extents according to the initial hydrocarbon concentration. Both facts influenced the hydrocarbon biodegradation kinetics. A sequential biodegradation of n-alkanes and UMC was found for the higher hydrocarbon content. Being the former growth associated, while UCM biodegradation was a non-growing process showing enzymatic-type biodegradation kinetics. For the lower hydrocarbon concentration, simultaneous biodegradation of n-alkanes and UMC were found before emulsification. Nevertheless, certain UCM biodegradation was observed after the medium emulsification. According to the observed kinetics, three main types of hydrocarbons (n-alkanes, biodegradable UCM and recalcitrant UCM) were found adequate to represent the multicomponent substrate (bilge waste) for future modelling of the biodegradation process.     

The effects of nutrient amendment on biodegradation and cytochrome P450 activity of an n-alkane degrading strain of Burkholderia sp. GS3C

The promotion of hexadecane biodegradation activity by an n-alkane degrading strain of Burkholderia cepacia (GS3C) with yeast extract amendment was studied using various carbon, nitrogen, vitamin, and amino acid amendments. Cytochrome P450 monooxygenase enzymes play a very important role and are especially required to introduce oxygen in n-alkane degradation. These enzymes from GS3C were located and detected using amino acid amendments. It was shown that biodegradation activity was promoted with amino acids amendments. However, only specific amino acids (L-phenylalanine, L-glutamic acid, L-proline, L-lysine, L-valine and L-leucine) have biodegradation promoting ability for GS3C. Cell protein concentration and cytochrome P450 activity were promoted significantly with the addition of L-phenylalanine and yeast extract. Furthermore, a significant positive linear relationship between cytochrome P450 activity and biodegradation efficiency of GS3C was observed. The results indicate that amino acid is the primary factor of nutrient amendment in promoting hexadecane biodegradation by influencing cytochrome P450 activity in GS3C.     

Combined effects of external mass transfer and biodegradation rates on removal of phenol by immobilized Ralstonia eutropha in a packed bed reactor

Biodegradation of phenol by calcium-alginate immobilized Ralstonia eutropha was carried out in a batch stirred and a packed bed reactor. In the batch system studies, the effect of initial phenol concentration on biodegradation was investigated at 30 degrees C and pH 7 while in the continuous system studies, the effects of flow rate and inlet phenol concentration on biodegradation were tested at the same temperature and pH. The observed biodegradation rate constant was calculated at different flow rates with the assumption of first-order biodegradation kinetics. Various external mass transfer correlations were evaluated and a new correlation of the type JD=K(NRe)(-(n-1)) was developed with the values of K=1.34 and n=0.65. The intrinsic first-order biodegradation rate constants and the external mass transfer coefficients were calculated then the combined effects of these rates on the observed first-order biodegradation rate constants were also investigated.     

聚乙烯醇生物降解的影响因素

研究了水溶性高分子聚乙烯醇(PVA)的生物降解性及其影响因素.结果表明,PVA的分子量、结晶度对其生物降解性具有决定作用.通过等离子体作用或氧化处理,可在PVA分子上引入＞C=O、-O=C-O、-COOH等基团,从而提高PVA的生物降解性和降解速率.     

聚丁二酸丁二醇酯及聚丁二酸/己二酸-丁二醇酯在微生物作用下的降解行为

研究了聚丁二酸丁二醇酯(PBS)及其共聚物聚丁二酸/己二酸-丁二醇酯(PBSA)薄膜在可控堆肥条件下的宏观生物降解行为,结果显示,PBS和PBSA薄膜具有良好的生物降解性能,降解过程经历三个阶段:诱导期、加速期和平坦期。对堆肥中的微生物进行分离和筛选,发现杂色曲霉菌对PBS和PBSA的生物降解能力最强。进一步研究PBS和PBSA薄膜在杂色曲霉菌作用下的微观生物降解行为,结果表明,PBSA薄膜比PBS薄膜具有更快的生物降解速率。