淀粉填充聚乙烯共混物的特性研究

研究了淀粉填充对ＨＤＰＥ、ＬＤＰＥ和ＨＤＰＥ／ＬＤＰＥ共混体系性能的影响。结果表明，随淀粉量的增加，共混物的力学性能有较大的下降。当加入少量增容剂后，共混物的拉伸强度得到明显提高，并可高于无淀粉填充体系的拉伸强度；淀粉填充共混物的出口膨胀效应比纯聚乙烯的明显减少。     

含淀粉与光敏剂的LDPE膜可控光生物降解

研究了含超淀粉及硬脂酸铁或Ｎ,Ｎ－二正丁基二硫代氨基甲酸铁／Ｎ,Ｎ－二正丁基二硫代氨基甲酸镍光敏剂的低密度聚乙烯膜光氧化降解羰基指数,粘均分子量和真菌侵蚀（级）的变化。结果表明,只需在ＬＤＰＥ膜中添加５％－１５％淀粉和０．１％－０．３％ＦｅＳｔ３或０．０５％－０．２０％ＦｅＤＢＣ／ＮｉＤＢＣ光敏剂,在自然曝露条件下可控ＬＤＰＥ膜的使用寿命 。     

MAH教枝LDPE对PET／LDPE共混物增容作用的研究

本文研究了马来酸酐在引发剂过氧化二异丙苯存在下，与ＬＤＰＥ在挤出机中进行熔融接枝反应，所得接枝物ＧＰＥ对ＰＥＴ／ＬＤＰＥ共混体系的增容作用。共混物的冲击强度及应力应变曲线结果表明，ＧＰＥ能明显改善共混体系的相容性，提高共混体系的冲击强度，仅用２０％的ＧＰＥ就能使共混物由脆性断裂变为韧性断裂。利用ＳＥＭ观察共混物的冲击断面形貌，结果表明，ＰＥＴ与ＬＤＰＥ完全不相容，ＧＰＥ能明显改善ＰＥＴ与ＬＤＰＥ共     

利用废旧塑料制土工排水带的研究

本文通过对回收ＬＤＰＥ／ＣａＣＯ３填充、回收ＬＤＰＥ／ＨＤＰＥ共混、回收ＬＤＰＥ／ＰＰ共混体系的研究，得出了较好力学性能的土工排水带板芯的配方．     

顺酐化三元乙丙橡胶改性PC／LDPE共混体系的研究

低密度聚乙烯（ＬＤＰＥ）可以改善聚碳酸酯（ＰＣ）的加工性能,并能在一定上改善ＰＣ的力学性能。顺酐化三元乙丙橡胶（ＭＥＰＤＭ）对ＰＣ／ＬＤＰＥ有增容作用,在ＰＣ／ＬＤＰＥ体系中加入１％左右的ＭＥＰＤＭ即可使冲击强度增加７０％。     

LLDPE熔融接枝丙烯酸及其应用的研究

以丙烯酸（ＡＡ）为接枝单体在Ｂｒａｂｅｎｄｅｒ中对ＬＬＤＰＥ进行熔融接枝改性研究，考察了共混温度、过氧化二异丙苯（ＤＣＰ）用量、ＡＡ用量以及混合时间对接枝率的影响，结果表明控制适当的反应条件率可达９％，而且反应温度以２２０℃左右为宜，ＤＣＰ用量不宜过高，以免引起严重的交联反应，研究ＬＬＤＰＥ－ｇ－ＡＡ对ＬＬＤＰＥ／淀粉可降解体系的增容效果表明，接枝物提高了ＬＬＤＰＥ／淀粉体系的拉伸强度，并且与淀粉     

纳米级无机粒子对聚乙烯的增强与增韧

对μｍ级ＣａＣＯ３、ＴｉＯ２和ｎｍ级ＳｉＣ／Ｓｉ３Ｎ４粒子填充ＬＤＰＥ的性能进行了研究。实验证明，μｍ级粒子对ＬＤＰＥ虽无明显的增强增韧作用，但也未使基体的机械性能大幅度下降。ｎｍ级ＳｉＣ／Ｓｉ３Ｎ４对ＬＤＰＥ有较大的增强增韧作用，在５％质量分数时冲击强度出现最大值，缺口冲击强度达５５．７ｋＪ／ｍ２为纯ＬＤＰＥ的２０３％；伸长率到６２５％时仍未断裂，为纯ＬＤＰＥ的５００％，但熔体流动速率急剧下降，仅为纯ＬＤＰＥ的２６％，当含量在３％和１５％质量分数时，熔体流动速率分别为纯ＬＤＰＥ的３３７％和１５１％。     

丙烯酸接枝聚乙烯增容LLDPE／淀粉共混体系研究

就丙烯酸接枝ＬＬＤＰＥ对ＬＬＤＰＥ／淀粉可生物降解共混体系力学性能的影响进行了研究,并对其与接枝改性淀粉的配合增容作用作了进一步探索。结果表明丙烯酸接枝ＬＬＤＰＥ可以明显提高ＬＬＤＰＥ和淀粉的相容性,共混体系拉伸强度可达１０．３５ＭＰａ,伸长率达１００％。此外,研究表明脲对提高体系拉伸强度有所帮助,但导致伸长率下降。     

mLLDPE及mLLDPE／LDPE共混物薄膜性能研究

研讨了茂金属线型低密度聚乙烯（ｍＬＬＤＰＥ）薄膜和ｍＬＬＤＰＥ与低密度聚乙烯（ＬＤＰＥ）共混物薄膜的物理性能和光学性能,并与传统的ＬＬＤＰＥ薄膜和ＬＬＤＰＥ／ＬＤＰＥ共混物薄膜进行了比较,表明ｍＬＬＤＰＥ薄膜和ｍＬＬＤＰＥ／ＬＤＰＥ共混物薄膜的性能优于传统的ＬＬＤＰＥ薄膜和ＬＬＤＰ／ＬＤＰＥ共混物薄膜,指出在ｍＬＬＤＰＥ中混合１０％ＬＤＰＥ,对薄膜性能影响不大。     

POM／LDPE共混改性新品级的研究

本文对ＰＯＭ／ＬＤＰＥ／增容剂共混增容改性进行了研究，研究结果表明：增容剂的加入，使ＰＯＭ／ＬＤＰＥ体系中ＬＤＰＥ分散均匀，ＰＯＭ球晶细化，物理力学性能得到改善，且增容剂的用量控制在５－７％为最佳。所研制的新品级的主要性能指标为：拉伸强度５０－６０ＭＰａ，缺口冲击强度≥１２ｋＪ／ｍ＾２，制作的小模数齿轮精度等级达７级，摩擦系数为０．２０－０．３０。     

可控光降解聚乙烯薄膜的研究

制备了硬脂酸铈（CeSt4）光敏剂。采用自制的CeSt4与硬脂酸锌（ZnSt2）、硬脂酸钙（CaSt2）、纳米二氧化钛（TiO2）等配合剂,制备出一种添加型的可控光降解聚乙烯（LDPE）薄膜。用红外光谱、粘均法测分子量和DSC等方法,对老化后的LDPE薄膜样品进行了表征。试验结果表明：CeSt4是一种很好的光敏剂;ZnSt2和CaSt2是有效的光降解促进剂,可缩短LDPE薄膜的光降解诱导期;改性纳米TiO2可延长LDPE薄膜光降解诱导期。     

Effect of pro‐oxidants on biodegradation of polyethylene (LDPE) by indigenous fungal isolate,Aspergillus oryzae

Proxidant additives represent a promising solution to the problem of the environment contamination with polyethylene film litter. Pro‐oxidants accelerate photo‐ and thermo‐oxidation and consequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. In the present study, fungal strain, Aspergillus oryzae isolated from HDPE film (buried in soil for 3 months) utilized abiotically treated polyethylene (LDPE) as a sole carbon source and degraded it. Treatment with pro‐oxidant, manganese stearate followed by UV irradiation and incubation with A. oryzae resulted in maximum decrease in percentage of elongation and tensile strength by 62 and 51%, respectively, compared with other pro‐oxidant treated LDPE films which showed 45% (titanium stearate), 40% (iron stearate), and 39% (cobalt stearate) decrease in tensile strength. Fourier transform infrared (FTIR) analysis of proxidant treated LDPE films revealed generation of more number of carbonyl and carboxylic groups (1630–1840 cm⁻¹ and 1220–1340 cm⁻¹) compared with UV treated film. When these films were incubated with A. oryzae for 3 months complete degradation of carbonyl and carboxylic groups was achieved. Scanning electron microscopy of untreated and treated LDPE films also revealed that polymer has undergone degradation after abiotic and biotic treatments. This concludes proxidant treatment before UV irradiation accelerated photo‐oxidation of LDPE, caused functional groups to be generated in the polyethylene film and this resulted in biodegradation due to the consumption of carbonyl and carboxylic groups by A. oryzae which was evident by reduction in carbonyl peaks. Among the pro‐oxidants, manganese stearate treatment caused maximum degradation of polyethylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

含羧酸铈光敏剂的LDPE地膜应用研究

研究了羧酸铈光敏剂及其配合体系的组成、各组分的协同关系和作用,讨论了其配合体系对聚乙烯地膜断裂伸长率、羰基指数和分子量的影响,并进行了农田覆盖地膜应用试验。结果表明,含羧酸铈光敏剂配合体系的聚乙烯地膜具有良好的使用性能和光降解可控性能。     

Effect of starch on thermal,mechanical, and barrier properties of low density polyethylene film

Low‐density polyethylene (LDPE) with different quantities of starch was compounded using a twin screw extruder and blown into films by a Konar K, blow‐film machine. Mechanical properties, namely percent elongation, tensile, bursting, and tear strength, as well as barrier properties, such as water vapor and oxygen transmission rate, of the filled LDPE film were studied. Thermal properties of the films were studied using DSC and DMA. Master curves at reference temperature of 30°C were obtained using software linked to DMA. Incorporation of 1% starch in LDPE has marginally affected the thermal, barrier, and mechanical properties; however, that of 5% starch filled LDPE has affected the properties to a great extent. The mechanical properties, such as percent elongation, tensile, tear, bursting, and seal strength, decreased by 19.2, 33.6, 3.60, 10.8, and 22.12%, respectively. Similarly, water vapor and oxygen transmission rate increased to 32.5 and 18.3%, respectively. Other physical properties, namely migration and thermal properties, were also affected in 5% starch filled LDPE; however, the film can still be used as packaging material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3355–3364, 2006     

The disintegration rate of traditional and chemically modified plastic films in simulated fresh- and sea-water environments

Six plastic films with varying chemical compositions in three different accelerated weathering environments were evaluated for disintegration. The films included two traditional films (LDPE and polystyrene), three with enhanced photodegradability (2% ECO and 10% ECO and LDPE with a vinyl ketone graft), and one with enhanced biodegradability (LDPE with 6% corn starch). The films were exposed to UVA-340 bulbs to simulate sunlight while in fresh water, salt water, or no water conditions. Disintegration of the films was determined by monitoring the change in physical properties of tensile strength at break, elongation at break, and toughness at break at selected intervals throughout the exposure period. Both the chemical composition of the film and the exposure environment produced significant differences in disintegration rates. Two of the films with enhanced photodegradability (2% and 10% ECO copolymers) disintegrated more rapidly than did the other films in this study. The environment where no water was present resulted in the fastest disintegration rate for the films when compared with the fresh-water environment. However, two films, LDPE and LDPE with 6% corn starch, degraded more rapidly in the salt-water environment than in the other two environments due to the presence of oxidation catalysts in the water system. © 1993 John Wiley & Sons, Inc.     

光降解聚乙烯薄膜的研究

合成并用FT-IR表征了硬脂酸铁(FeSt3)光敏剂。采用自制光敏剂与纳米二氧化钛(TiO2)制备出可光催化降解薄膜,通过人工加速紫外老化降解试验,测定了含有光敏剂的低密度聚乙烯(LDPE)薄膜的力学性能、FT-IR谱图和黏均相对分子量的变化。结果表明:硬脂酸铁(FeSt3)对LDPE具有很强的光催化降解作用,并且含量越高,光催化作用越强;纳米TiO2可以延缓LDPE的降解诱导期,且随着其含量增大,效果越明显。     

Effect of Morphology on the Biodegradation of Thermoplastic Starch in LDPE/TPS Blends

In this study, thermoplastic starch (TPS) was mixed with low density polyethylene with different melt flow indexes in a one-step extrusion process to produce LDPE/TPS blends varied from 32% to 62% by weight of TPS. The influence of starch content and LDPE viscosity on morphology, biodegradation and tensile properties of LDPE/TPS blends were evaluated. Starch continuity and biodegradability were studied by hydrolytic, enzymatic and bacterial degradation. The LDPE viscosity had a considerable effect on the morphology and the connectivity of the starch particles. Evaluation of hydrolytic extraction showed that blends having TPS content above 50 wt% possessed a full connectivity. Studies of biodegradation indicated that the bacterial attack on starch resulted in weight loss of TPS of 92%, 39% and 22%, for PE1/TPS having 62% and 32% TPS, and PE2/TPS (31% TPS), respectively. Comparatively, the weight loss was more significant at 100%, 66% and 31% by hydrolytic extraction. Differences between these two techniques were discussed in terms of the accessibility of starch domains to microorganisms. Tensile properties (ε_b and E) decreased with increasing exposure time to activated sludge. Changes in tensile properties were highly dependent on the biodegradation rate. PE1/TPS blends having 32% starch remained ductile after 45 days of exposure to bacterial attack.     

Transparent low‐density polyethylene/starch nanocomposite films

Low‐density polyethylene (LDPE)/starch nanocomposite films were prepared by melt extrusion process. The first step includes the preparation of starch–clay nanocomposite by solution intercalation method. The resultant product was then melt mixed with the main matrix, which is LDPE. Maleic anhydride‐grafted polyethylene (MAgPE), produced by reactive extrusion, was used as a compatibilizer between starch and LDPE phases. The effects of using compatibilizer, clay, and plasticizers on physico‐mechanical properties were investigated. The results indicated that the initial intercalation reaction of clay layers with starch molecules, the conversion of starch into thermoplastic starch (TPS) by plasticizers, and using MAgPE as a compatibilizer provided uniform distribution of both starch particles and clay layers, without any need of alkyl ammonium treatment, in LDPE matrix. The nanocomposite films exhibited better tensile properties compared to clay‐free ones. In addition, the transparency of LDPE film did not significantly change in the presence of TPS and clay particles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thermogravimetric determination of starch content in starch–polyethylene blend films

Thermogravimetric analysis as a technique for rapid determination of starch content in LDPE/starch blend films was investigated. The percent weight loss in a specified temperature range, under a constant heating rate, correlated well with the starch content of films in the range of 0–12 wt % starch, as determined by chemical analysis. The method was used to estimate the residual starch content of LDPE/starch films, containing approximately 6.0% starch, exposed under several biotic exposure conditions. Generally 87–88% of the initial starch content was present in the films after different types of environmental exposures.     

Manganese stearate initiated photo‐oxidative and thermo‐oxidative degradation of LDPE,LLDPE and their blends

This study is an attempt to investigate the effect of a representative pro‐oxidant (manganese stearate) on the degradation behavior of 70 ± 5 μ thickness films of LDPE, LLDPE and their blends. Films were prepared by film blowing technique in the presence of varying quantities of manganese stearate (0.5–1% w/w) and subsequently subjected to accelerated degradative tests: xenon arc exposure and air‐oven exposure (at 70°C). The physico–chemical changes induced as a result of aging were followed by monitoring the mechanical properties (Tensile strength and Elongation at break), carbonyl index (CI), morphology (SEM), melt flow index (MFI), oxygen content (Elemental analysis), and DSC crystallinity. The results indicate that the degradative effect of pro‐oxidant is more pronounced in LDPE than LLDPE and blends, due to the presence of larger number of weak branches in the former. The degradation was also found to be proportional to the concentration of the pro‐oxidant. Flynn‐Wall‐Ozawa iso‐conversion technique was used to determine the kinetic parameters of degradation, which were used to determine the effect of the pro‐oxidant on the theoretical lifetime of the polymer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010