真菌BFM-X1对聚丁二酸丁二醇酯薄膜的降解过程

对菌株Bionectria sp.BFM-X1(简称BFM-X1)分别利用不同碳源对聚丁二酸丁二醇酯(PBS)薄膜的降解情况及降解后的残留膜进行了观察分析,揭示PBS薄膜的微生物降解过程.结果表明:菌株分别以PBS乳剂、葡萄糖、大豆油及甘油为唯一碳源时均能有效降解PBS薄膜；降解过程表现为表面失去光泽期、裂纹状结构期、破碎期和完全降解期4个阶段,并存在迟滞期,且葡萄糖碳源下的降解速率快于其他碳源的；菌株的菌丝能在PBS膜表面上扩展生长是该菌株降解PBS的前提,真菌的寄生作用是前期降解的主要动力；降解过程中胞外酶的水解作用使聚合物的酯键水解,生成可被菌株同化吸收的小分子；菌株BFM-X1对PBS薄膜的降解首先发生在膜表面,非结晶部分先于结晶部分被降解.     

改性淀粉材料生物降解性分析体系的建立及应用

测定了热塑性淀粉(TPS)和热塑性双醛淀粉(TPDAS)在堆肥条件下的生物降解能力。根据ISO 14855建立了一套新的测试体系并且验证了这个体系测定高分子材料生物降解性能的可行性。对热塑性淀粉材料生物降解性的测试结果发现化学改性对于淀粉的降解速率和降解速度都有很大的影响。在可控堆肥条件下TPS比TPDAS降解的要快。TPDAS的降解速度和最终的生物降解百分率和双醛淀粉(DAS)的氧化度有密切的关系。文中讨论了存在这种关系的可能原因。有不同降解速率的TPS和TPDAS的降解过程呈现出三个阶段,即迟滞阶段。降解阶段和平稳阶段。     

PBS基生物降解材料的研究进展

PBS(聚丁二酸丁二醇酯 )是一种具有良好生物降解性的聚酯塑料。本文简述了PBS的基本特性、降解机理和制备方法 ,对各种PBS基生物降解材料的特性进行了分析 ,介绍了PBS基生物降解材料的研究进展     

纤维素纤维材料几种降解方法的研究

测试和比较了天然棉纤维织物和几种人造可再生纤维素纤维(竹原纤维、莫代尔纤维和天丝纤维)在实验室条件下和大环境堆肥条件下的生物降解性.生物降解行为的测试分别采用ASTM D5988-03、堆肥法和酶催化降解法,以比较几种织物在自然环境和微生物培养基条件下的降解速度;结合红外光谱通过分析降解前后结构的改变研究不同的降解方法对纤维素材料的降解程度.结果表明纤维素类纤维织物均表现出良好的生物降解性,并且人造可再生纤维素纤维的降解速度高于天然棉纤维.和传统的实验室条件下测量织物降解性的方法相比,堆肥中含有更多的微生物和酶活性组分,加速了纤维素材料的分解.     

高填充可降解淀粉基聚烯烃材料的制备及其堆肥降解

制备了高填充的聚乙烯（PE）-淀粉-碳酸钙（CaCO3）三元复合材料,根据ASTM D6400标准对该材料进行了堆肥降解。采用熔体流动速率（MFI）、差示扫描量热分析（DSC）、扫描电镜分析（SEM）等方法研究了该复合材料的堆肥降解行为。结果表明：堆肥降解过程中,熔体流动速率（MFI）在堆肥1个月左右出现极小值;降解过...     

聚琥珀酸丁二酯的辐射交联及其生物降解性

对聚琥珀酸丁二酯（PBS1）采用两步法辐照，比其它辐照法得到的凝胶含量高，这是由于在室温下预先辐射所形成的交联网络结构减少了聚合物的降解。交联后的PBS1有较高的耐热变形性。通过酶降解试验和土需求量法降解实验，PBS1有很高的生物降解性，即使它产生了很高的交联结构。在65℃时，酶的降解率最高。由于交联样品所含有的交联网络结构阻碍它的降解，交联PBS1的生物降解失重低于未交联样品。     

高分子材料生物降解性能的分析研究进展

本文介绍了近年来生物降解材料降解方法的研究现状,主要从不同的降解环境,包括在堆肥环境、水性环境、惰性固体介质环境等进行的材料生物降解性能研究进行了比较、评述与展望。     

天然高分子/聚丁二酸丁二醇酯共混物研究进展

聚丁二酸丁二醇酯(PBS)是一种热塑性脂肪族聚酯,因力学和生物降解性等性能良好而具有广泛应用前景,但仍存在拉伸强度和生物降解速率低,成本高等缺陷,限制了其应用。通过物理改性是提高其性能和应用领域的重要研究方向之一。本文综述了近年天然高分子/PBS共混物制备和性能研究,并对天然高分子/PBS共混物的发展作了总结和展望。     

末端带有磷酰胆碱基团的聚丁二酸丁二醇酯的合成、表征和性能研究

采用四步反应合成了一种新的具有良好生物相容性和生物降解性的末端带有磷酰胆碱(PC)基团的聚丁二酸丁二醇酯PBS-PC. 采用1H NMR、IR、凝胶色谱(GPC)和X射线光电子能谱(XPS)表征了聚合物的结构. 同时研究了聚合物的亲疏水性能、体外降解、溶胀率和对模型药物中性红的缓释性能. 结果显示: PC基团引入, 在一定程度上提高了PBS的亲水性、降解速率、溶胀率和对中性红的缓释性能.     

热裂解-气相色谱-质谱法鉴别生物可降解塑料

目前生物可降解塑料主要采用堆肥降解测定其生物降解性能的方法进行鉴别,其检测周期长、费用较高。材料的组成基本决定了其生物降解特性,为了快速鉴别生物可降解塑料,采用热裂解-气相色谱-质谱法(PY-GC-MS)对以聚对苯二甲酸-己二酸丁二醇酯(PBAT)与不同质量比的其他成分包括生物可降解聚乳酸(PLA)、难降解材料聚苯乙烯(PS)或聚对苯二甲酸乙二醇酯(PET)混合样的裂解特征进行了研究。结果显示,PBAT的裂解特征峰明显,未受到PLA的影响;若在PBAT中添加质量分数1%的非降解材质PS和PET也可被检出。方法用于市场上收集到的标识为可降解塑料购物袋样品的分析,结果表明,采用PY-GC-MS可以快速对可降解塑料进行初步鉴别。     

Cellulose acetate butyrate as multifunctional additive for poly(butylene succinate) by melt blending: Mechanical properties, biomass carbon ratio, and control of biodegradability

We have evaluated the plasticizing effect of poly(butylene succinate) (PBS) and cellulose acetate butyrate (CAB). PBS and CAB were mixed with a melt-kneading machine. The tensile strength and strain at break in the case of the blend with 10% CAB in the PBS matrix were 547% and 35 MPa. It showed that CAB acted as a plasticizer for PBS. The biomass carbon ratio of the blends measured by accelerator mass spectrometry based on ASTM D6866 showed that the biomass carbon derived from a part of the CAB corresponded to the theoretical value of the polymer blend. The biodegradation of PBS with the CAB melt blend powders was evaluated by a microbial oxidative degradation analyzer under controlled compost conditions based on ISO 14855-2. PBS with 10% CAB was not degraded within 60 days due to the addition of CAB that could control the biodegradability of the PBS.     

Degradation of the blends of natural and synthetic copolyesters in different natural environments

The paper presents results of the biodegradation of the blends of natural and synthetic copolyesters in two different natural environments. Environmental degradation took place in compost with activated sludge at sewage farm and - for comparison - in the Baltic Sea in Gdynia Harbour. Degradation of these blends was monitored for 16 weeks in compost and for 6 weeks in sea water. The changes in macroscopic features of surface and the weight loss of the samples were measured during the performed experiment. The characteristic parameters of compost and sea water were also controlled during all incubation time and their influence on the rate of biodegradation is discussed. The results of this study revealed that the natural aliphatic copolyester i.e. 3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and its blends with the synthetic aliphatic-aromatic copolyester of 1,4-butandiol with adipic and terephthalic acids degrade faster in compost than in sea water. The rate of the biodegradation process depends on the composition of blends and different abiotic parameters of compost and sea water.     

Biodegradation of poly(lactic acid) and its nanocomposites

PLA nanocomposites based on organically modified montmorillonites at 5% w/w loading were prepared by melt blending using an internal mixer and then degraded in a commercial compost. The addition of nanoclays was found to increase the PLA degradation rate, especially for the highest dispersed clay in the polymer matrix. Biodegradation by microorganisms isolated from the compost showed the bacterium Bacillus licheniformis as one of the responsible for PLA biodegradation in compost. It was also found that clays can influence the polymer bacterial degradation depending on their chemical structure and affinity of the bacterium towards the clay.     

Biodegradation and hydrolysis rate of aliphatic aromatic polyester

The biodegradation and hydrolysis rates of an aliphatic aromatic copolyester were measured in manure, food, and yard compost environments and in phosphate buffer solution (pH = 8.0) and vermiculite at 58 °C. Mineralization, molecular weight reduction, and structural changes determined by DSC, FTIR, and ¹H NMR were used as indicators of the biodegradation and hydrolysis rates. Poly(butylene adipate-co-terephthalate), PBAT, film biodegraded at distinctive rates in manure, food, and yard compost environments having different microbial activities. The highest biodegradation rate was found in manure compost, which had the highest CO₂ emissions and lowest C/N ratio. The possible presence of extracellular enzymes in manure and food composts may facilitate the hydrolytic reaction since greater molecular weight reduction rates were observed in these composts. ¹H NMR and thermal analysis revealed that, while PBAT is a semi-crystalline copolyester with cocrystallization of BT and BA dimers, the soft aliphatic domain (BA) and the amorphous region are more susceptible to hydrolysis and biodegradation than the rigid aromatic domain (BT) and the crystalline region.     

Polycyclic Aromatic Hydrocarbons (PAHs) Biodegradation by Basidiomycetes Fungi, Pseudomonas Isolate, and Their Cocultures: Comparative In Vivo and In Silico Approach

The polycyclic aromatic hydrocarbons (PAHs) biodegradation potential of the five basidiomycetes' fungal monocultures and their cocultures was compared with that of a Pseudomonas isolate recovered from oil-spilled soil. As utilization of hydrocarbons by the microorganisms is associated with biosurfactant production, the level of biosurfactant production and its composition by the selected microorganisms was also investigated. The Pseudomonas isolate showed higher ability to degrade three of the five PAHs but the isolate did not produce biosurfactant higher than C. versicolor and P. ostreatus. Among the PAHs, the most effective biodegradation of PAH--pyrene (42%)--was obtained with the fungus C. versicolor. Cocultures involving the fungi and Pseudomonas could not significantly degrade the selected PAHs compounds above that degraded by the most efficient monoculture. A slight increase in pyrene degradation was observed in cocultures of C. versicolor and F. palustris (93.7% pyrene). The crude biosurfactant was biochemically characterized as a multicomponent surfactant consisting of protein and polysaccharides. The PAH biodegradation potential of the basidiomycetes fungi positively correlated with their potential to express ligninolytic enzymes such as lignin peroxidase (Lip), manganese peroxidase (Mnp), and laccase. The present study utilized in silico method such as protein-ligand docking using the FRED in Open Eye software as a tool to assess the level of ligninolytic enzymes and PAHs interactions. The in silico analysis using FRED revealed that of the five PAHs, maximum interaction occurred between pyrene and all the three ligninolytic enzymes. The results of the in silico analysis corroborated with our experimental results showing that pyrene was degraded to the maximum extent by species such as C. versicolor and P. ostreatus.     

Biodegradability of bio-flour filled biodegradable poly(butylene succinate) bio-composites in natural and compost soil

This study investigated the biodegradability of PBS and bio-flour, which is a poly(butylene succinate) (PBS) bio-composite filled with rice-husk flour (RHF) reinforcing, in natural and aerobic compost soil. The percentage weight loss and the reduction in mechanical properties of PBS and the bio-composites in the compost soil burial test were significantly greater than those in the natural soil burial test. These results were supported by degraded surface of PBS and bio-composites observed through morphological study and the total colony count of natural soil was lower than that of compost soil. The biodegradability of the bio-composites was enhanced with increasing bio-flour content because the bio-flour is easily attacked by microorganisms. As the biodegradability test progressed over time up to 80 days, the molecular weight of PBS decreased in the soil burial test. We confirmed by attenuated total reflectance (FTIR-ATR) analyser that the chemical structures of PBS and the bio-composites were changed after the compost burial test. The glass transition temperature (T_g), melting temperature (T_m), crystallization temperature (T_c), heat of fusion (ΔH_f) and heat of crystallization (ΔH_c) of the natural and composted soil tested PBS were investigated using differential scanning calorimetry (DSC). From the results, we concluded that use of these bio-composites will reduce the environmental problems associated with waste pollution and the study findings support the predicted application of bio-composites as “green-composites” or “eco-materials”.     

脂肪族聚酯及共聚酯的生物降解性研究

以酯交换法或直接缩聚法合成了一系列脂肪族聚酯，经二异氰酸酯(HDI)扩链得到含氨酯键的聚酯及共聚酯，用DSC、X射线衍射等分析表征了聚酯及共聚物的结构和性能。用土埋试验、CO2释放试验和黑曲霉降解试验着重研究了这些聚合物的生物降解性，详细讨论了聚酯结构、组成及聚酯分子量对生物降解性的影响。     

A simple method suitable to test the ultimate biodegradability of environmentally degradable polymers

A straightforward experimental set-up derived from the Biometer Flask previously utilized for experiments of pesticides biodegradation, has been adopted for testing the ultimate biodegradability of natural, synthetic and semi-synthetic polymeric materials on solid substrates such as soil and mature compost. The use of these whole substrates as incubation media in respirometric experiments, may negatively affect the accuracy of the test due to the large amount of carbon dioxide developed from the blanks, especially in the presence of specimen degrading at low or moderate rates. In the present test procedure soil and compost samples are diluted with perlite, a naturally occurring inert aluminum silicate widely utilized in horticultural applications, in order to ensure optimal conditions for the microbial growth while reducing the carbon dioxide emissions from the blanks. The results so far reported clearly indicate that the adopted procedure is extremely valuable and versatile for the appreciation of even subtle differences in the biodegradation rate of different polymeric materials, as well as for long-term degradation experiments.     

Abiotic and biotic degradation of oxo-biodegradable polyethylenes

Conventional polymeric materials accumulate in the environment due to their low biodegradability. However, an increase in the biodegradation rate of these polymers may be obtained with the addition of pro-degrading substances. This study aimed to evaluate abiotic and biotic degradation of polyethylenes (PEs) using plastic bags of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) formulated with pro-oxidant additives as test materials. These packaging materials were exposed to natural weathering and periodically analyzed with respect to changes in mechanical and structural properties. After a year of exposure, residue samples of the bags were incubated in substrates (compost of urban solid waste, perlite and soil) at 58 °C and at 50% humidity. The biodegradation of the materials was estimated by their mineralization to CO₂. The molar mass of the pro-oxidant-activated PE decreased and oxygen incorporation into the chains increased significantly during natural weathering. These samples showed a mineralization level of 12.4% after three months of incubation with compost. Higher extents of mineralization were obtained for saturated humidity than for natural humidity. The growth of fungi of the genera Aspergillus and Penicillium was observed on PE films containing pro-oxidant additives exposed to natural weathering for one year or longer. Conventional PE films exposed to natural weathering showed small biodegradation.