A new method for the evaluation of biodegradable plastic using coated cellulose paper

A highly sensitive analytical method for evaluation of poly(L-lactide) (PLA), poly(epsilon-caprolactone) (PCL), poly(beta-hydroxybutyrate) (PHB), and poly(butylene succinate) (PBS) degradability was developed using coated cellulose paper, prepared by penetration and adhesion of these plastics into/onto the cellulose paper. Enzymatic degradability of the obtained plastic coated papers was evaluated using various commercial proteases and lipases. PLA coated paper was highly susceptible to subtilisin and mammalian enzymes, alpha-chymotrypsin, elastase and trypsin. To our knowledge, this is the first report on the degradation of PLA coated paper using subtilisin and mammalian enzymes. Almost all lipase preparations degraded PCL and PHB coated papers but not PBS coated paper. The biodegradability of plastic coated paper was greater than that of plastic powder. The penetration of plastic into cellulose paper by coating improved the plastic degradability, and can be regulated easily.     

阻垢剂的可生物降解性研究

参照OECD301B标准,以降解过程中的二氧化碳生成量作为表征指标,研究了五种常用阻垢剂和两种新型阻垢剂的可生物降解性,得出了阻垢剂的可生物降解性数据、生物降解规律及聚合物分子结构与可生物降解性的关系。研究结果表明,增加聚羧酸阻垢剂分子结构中羧基的数目、酯基支链以及向主链中插入氮、氧元素,均可提高其可生物降解性,后两种方法特别有效。     

二步法腈纶废水有机污染物的理论生物降解性

二步法腈纶废水中含有的有机污染物种类为腈类,酚类,烷烃类,酰胺类,表面活性剂及其它芳香族物质等,运用相关科知识研究了其中含有的主要有机污染物的化学结构与其生物降解性能的关系,深入分析研究了它们的理论生物降解性能,并进行了分类。     

魔芋纤维发泡海绵制作工艺改进及其性能研究

以魔芋胶为原料,选择无毒性的交联剂、发泡剂等试剂来制备魔芋纤维发泡海绵.通过反复多次试验,制备出内部空隙直径约2~3 mm、吸水率范围约在6%~19%之间的魔芋纤维发泡海绵,并探究了在不同发泡剂与交联剂用量下魔芋纤维发泡海绵的性能,研究了制作工艺对产品性能的影响.以魔芋胶80~100 g、发泡剂2~4 g、交联剂4 g、增韧剂2 g、浸润剂4 g、增塑剂10 g加入1 L水中搅拌均匀后升温至100~110℃,保温1.5 h所制得的魔芋纤维发泡海绵具有良好的强度、吸水性能和生物降解性.     

Improving polyethylene–octene elastomer/chitosan by graftation of acrylic acid onto polyethylene–octene elastomer—mechanical properties and biodegradability examination and composites characterization

In this study, the properties of polyethylene–octene elastomer/chitosan (POE/chitosan) and acrylic acid (AA)‐grafted‐polyethylene–octene elastomer/chitosan (POE‐g‐AA/chitosan) were examined using various characterizing instruments. Mechanical and thermal properties of POE deteriorated noticeably when it was blended with chitosan, due to the unsatisfactory compatibility between the two phases. The greater compatibility of POE‐g‐AA with chitosan, due to the formation of ester carbonyl and imide groups, led to a much better dispersion and homogeneity of chitosan in the POE‐g‐AA matrix and consequently to noticeably better mechanical properties. Furthermore, with a lower melting point temperature, the POE‐g‐AA/chitosan blend was more easily processed than POE/chitosan. POE‐g‐AA/chitosan had a higher water resistance than POE/chitosan. Both blends suffered weight loss when buried in soil, especially at high levels of chitosan substitution, indicating that both were biodegradable. The mechanical properties of both blends, such as tensile strength and elongation at break, also deteriorated after being buried in soil. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3882–3891, 2003     

关于提高工业废水可生化性的方法探讨

简述了提高工业废水的可生化性原因,介绍了工业废水可生化性的鉴别方法,提出了提高工业废水可生化性的方法。     

ClO2催化氧化处理土霉素废水处理站二级出水

以土霉素废水处理站二级出水为研究对象,二氧化氯(ClO2)为氧化剂,以自制活性炭负载铜氧化物(CuOx-AC)催化剂进行ClO2催化氧化试验研究。试验结果表明,ClO2催化氧化最佳反应条件为初始反应pH值为7.0、ClO2投加量为0.24g/L(折纯,质量浓度)、催化剂投加量为50g/L(质量浓度)和反应时间为30min。在此条件下,废水COD的质量浓度由472.7～523.4mg/L降至301.2～340.1mg/L,COD去除率在35%左右,但废水B/C值由0.04～0.07提高至0.21～0.24,可生化性显著提高,为进一步采取生化处理工艺实现废水达标排放奠定了基础。     

含氮杂环化合物冲击负荷对厌氧滤池-曝气生物滤池工艺处理焦化废水的影响

采用生物强化及未生物强化厌氧滤池(AF)–曝气生物滤池(BAF)两套反应器处理焦化废水, 并研究外加杂环化合物咔唑、喹啉和吡啶对工艺处理效果的影响。结果表明: 未添加杂环化合物, 两套AF-BAF反应器系统厌氧段COD的去除率均为35%, 厌氧出水可生化性从进水的0.33上升为0.59; 添加100 mg/L咔唑后, 生物强化反应器厌氧段COD去除率仍维持在35%, 出水可生化性变为 0.53, 未生物强化反应器厌氧段COD去除率降为23%, 出水可生化性降为 0.45; 同时添加100 mg/L喹啉和50 mg/L吡啶, 生物强化反应器厌氧段COD的去除率降为27%, 出水可生化性降为0.48, 未生物强化反应器厌氧段COD去除率降为12%, 出水可生化性降为0.38。生物强化有效地提高了反应器对高浓度杂环化合物的耐冲击能力。高效液相色谱结果显示, 外加的咔唑、喹啉和吡啶在生物强化反应器厌氧段的去除率可达83%, 91%和88%, 而在未生物强化反应器厌氧段的去除率仅为57%, 66%和55%。气相色谱–质谱分析表明, 外加杂环化合物导致生物强化反应器厌氧出水烷烃与含苯环酯类物质种类的增加。研究结果揭示了高浓度杂环化合物咔唑、喹啉和吡啶负荷对A/O工艺处理焦化废水效果的影响。     

State of the Art of Small‐Diameter Vessel‐Polyurethane Substitutes

Cardiovascular diseases are a severe threat to human health. Implantation of small‐diameter vascular substitutes is a promising therapy in clinical operations. Polyurethane (PU) is considered one of the most suitable materials for this substitution due to its good mechanical properties, controlled biostability, and proper biocompatibility. According to biodegradability and biostability, in this review, PU small‐diameter vascular substitutes are divided into two groups: biodegradable scaffolds and biostable prostheses, which are applied to the body for short‐ and long‐term, respectively. Following this category, the degradation principles and mechanisms of different kinds of PUs are first discussed; then the chemical and physical methods for adjusting the properties and the research advances are summarized. On the basis of these discussions, the problems remaining at present are addressed, and the contour of future research and development of PU‐based small‐diameter vascular substitutes toward clinical applications is outlined.