排序方式: 共有51条查询结果,搜索用时 15 毫秒
41.
Emo Chiellini Andrea Corti Arianna Giovannini Piero Narducci Anna M. Paparella Roberto Solaro 《Journal of Polymers and the Environment》1996,4(1):37-50
The results of an investigation aimed at evaluation of the biodegradability of blends of poly(-caprolactone) (PCL) with poly(ethylene terephthalate) (PET) as the major component are reported. Specimens of the blends, as melt extruded films and/or powders, were submitted to degradation tests under different environmental conditions including full-scale composting, soil burial, bench-scale accelerated aerobic degradation, and exposure to axenic cultures and esterolytic enzymes. Indications have been gained that blending in the melt gives rise to insertion of PCL segments in the PET chain. Copolymers thus attained acted as macromolecular compatibilizers, allowing for a complete miscibility of PCL and PET. The biodegradation detected on the blend samples was, however, well below the values expected from chemical composition and behavior of individual homopolymers under the same environmental conditions. The presence of PET as the major component in PET/PCL blends apparently reduces the propensity of PCL to be degraded, at least in the investigated composition range. The degradation data collected under different environmental conditions indicate that the full-scale composting system is the most efficient among the tested degradation procedures. 相似文献
42.
The rheological behavior of biodegradable blends of starch and poly(vinyl alcohol) (PVOH) was measured as a function of temperature, shear rate, and moisture content using a capillary rheometer. An excellent correlation was found with a rheological model which was used as a means to characterize the influence of starch/PVOH content as well as a qualification of the viscosity for simulation studies. This model consisted of a power law dependence on shear rate, an Arrhenius dependence on temperature, and an exponential dependence on moisture.Paper presented at the Biodegradable Materials and Packaging Conference, September 22–23, 1993, Natick, Massachusetts.Guest Editor: Dr. Randall Shogren, USDA. 相似文献
43.
Xuefeng Liu Shijie You Fang Ma Hao Zhou 《Frontiers of Environmental Science & Engineering》2021,15(4):53
44.
Deepak Srivastava 《Journal of Polymers and the Environment》2004,12(1):27-33
Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature. 相似文献
45.
污泥和煤混烧特性的热重分析法研究 总被引:10,自引:2,他引:10
为了解城市污泥和煤粉混烧的燃烧规律,利用热重分析法对兰坝煤粉和某城市污泥及两试样混合物的燃烧特性进行了研究.实验结果表明,在加热速度20℃·min-1、20~1200℃的温度范围内,污泥的热重曲线存在2个明显的失重区域.在混燃过程中,煤和城市污泥基本上保持了各自的挥发分析出特性,混合试样的燃烧曲线处于污泥和煤粉燃烧曲线之间.对实验数据进行分析处理,得到了反应动力学参数活化能E和频率因子A.在掺混比例较小时(污泥质量分数为20%)对煤的活性几乎没有什么影响;而掺混比例较大时(污泥质量分数为50%、80%),存在2个反应区间,在第一温度段(大约θ<430℃)混合试样的反应特性类似于污泥,而在高温区段(θ>430℃)混合试样的燃烧特性则类似于煤. 相似文献
46.
以混合柴油为靶污染物,通过对比实验研究了油污染物在模拟水环境中的降解效果。研究表明,模拟自然条件下混合柴油污染物总体降解较慢,油质去除率低;生物强化降解条件下,向混合柴油污染水样中添加驯化培养的微生物混合菌群,生物降解速率明显提高,油质去除率达到98%以上。研究还发现,各污染水样中油的降解速率与降解效果随柴油的配比而不同,混合柴油样本中生物柴油的比例越高,样本的降解率越高,表明生物柴油作为碳源有效改善了水中有机营养配比,促进了柴油的去除效果。进一步分析表明,混合柴油在水中的降解过程符合一级反应动力学,生物强化降解条件下,生物柴油比例越高,混合柴油降解速率越快,除油微生物以菌胶团、球菌和丝状菌为主。 相似文献
47.
煤矸石制取聚合氯化铝原理及工艺 总被引:9,自引:0,他引:9
介绍了固体废物煤矸石制取混凝剂聚合氯化铝的基本原理及工艺流程,通过技术与经济分析,确立了煤矸石开发利用的新领域. 相似文献
48.
Charles M. Buchanan Barry G. Pearcy Alan W. White Matthew D. Wood 《Journal of Polymers and the Environment》1997,5(4):209-223
The miscibility of cellulose acetate (CA; degree of substitution = 2.5) and poly(ethylene succinate) (PES) has been investigated
using a variety of thermal techniques and by solid-state carbon13 NMR spectroscopy. The blends containing greater than ca.
70% CA were found to be miscible. In the case of blends containing less than ca. 70% CA, a combination of thermal and NMR
analyses suggests that these blends are not fully miscible on a 2.5- to 5-nm scale. On the scale which can be probed by dynamic
mechanical thermal analysis (15 nm), the low-percentage CA blends exhibit “significant local concentration fluctuations≓.
Investigation of the biodegradation of the blend components and of the blends revealed that PES degraded relatively rapidly
and that CA degraded slowly. The blends degraded at a rate essentially identical to that of CA. Miscibility (75% CA blend)
or crystallization of PES (30% CA blend) had no significant effect. These data suggest that a significant mode of degradation
ófPES during composting involves chemical hydrolysis of the polymer followed by biological assimilation of monomers. Degradation
of the blends is initiated in the amorphous phase. Because CA is a significant component of the amorphous phase, a small amount
of CA significantly impacts the biodegradation rates of the blends. 相似文献
49.
Huan Xi Fanlu Min Zhanhu Yao Jianfeng Zhang 《Frontiers of Environmental Science & Engineering》2023,17(6):71
50.
含油乳化废水处理的应用研究 总被引:1,自引:0,他引:1
简述了含油乳化废水常用的破乳工艺。以生产润滑油的某调合厂为实例,通过絮凝剂的筛选,采用复合型破乳剂聚合硫酸铝(PAS)作为絮凝剂进行化学破乳工艺试验,设计了破乳、气浮、活性炭吸附处理及附加条件的5种试验。结果表明,聚合硫酸铝与阴离子(非离子)复合型破乳剂能有效地对调合厂含油乳化废水进行破乳,每吨废水分别加500mL的聚合硫酸铝(浓度为10%)和500mL的阴离子PAM(浓度为0.1%),停留时间为5min,即能完成破乳及油水分离过程,废水处理药剂费用为0.25元/t左右,在原水COD2894mg/L时,COD去除率达到96.8%。经处理后的排放废水能够达到国家规定的排放标准。 相似文献