聚丙烯土工合成材料的老化与防老化

以长江口深水航道治理工程为例，通过大气老化试验考察了所开发的聚丙烯土工合成材料中聚阻胺类防老化剂和聚酯纤维物理防护的作用，并验证了紫外辐射对聚丙烯老化的影响。     

分离大豆蛋白凝胶光学性质的研究

深入地研究了分离大豆蛋白凝胶的透明性与ｐＨ值,加热温度、蛋白质浓度、离子强度（ＮａＣｌ浓度）和葡萄糖酸－δ－内酯（ＧＤＬ）的关系。结果表明：在ｐＨ〈３．５或ｐＨ〉５．５,温度〉８０℃、蛋白质浓度〉２．５％、低离子强度（ＮａＣｌ浓度〈１０ｍｏｌ／Ｌ）和无葡萄糖酸－δ－内酯的条件下,有利于形成透明性分离大豆蛋白凝胶。可为进一步研究大豆蛋白凝胶的光学性质和研制透明的大豆蛋白产品提供理论依据。     

聚丙烯非织造布的光老化研究

采用拉伸性能、差示扫描量热法(DSC)、红外光谱分析仪等现代化的分析手段,研究了普通聚丙烯非织造布与抗老化非织造布在紫外老化和自然老化过程中的性能变化,分析了其不同及机理,得出了适合的紫外老化条件。     

聚丙烯非织造布加速老化性能研究

为研究聚丙烯非织造布的老化失效特征,采用紫外辐射对材料进行加速老化试验,评估材料老化前后的表观形貌、热性能、分子结构和力学指标变化。结果表明：聚丙烯非织造布的老化特征包括纤维显著黄化、脱落,断裂强度和断裂伸长显著降低,其老化降解机制与分子链断裂和晶粒尺寸减小密切相关。     

紫外线辐射强度对聚丙烯长丝光氧老化的影响

以聚丙烯长丝为对象,采用不同紫外线辐射强度的人工加速老化试验对其光氧老化过程进行研究.对老化过程中试样的断裂强力进行测试,并进行红外光谱分析.测试结果表明:采用2根和4根紫外荧光灯管的老化结果之间相关性较好,而与8根灯管老化结果之间的相关性较差.造成这种差别的原因在于,2根和4根灯管老化条件下的降解产物与8根灯管老化条件下的降解产物有所不同,即过高的紫外线辐射强度会导致聚丙烯长丝光氧老化动力学过程的改变.     

无定形食品物理老化过程的数值研究

为了估算无定形食品的老化时间,利用数值方法考察了升降温速率和Adam-Gibbs(AG)模型参数对连续升降温无量纲比热容的影响。结果表明,升降温速率会对计算结果产生明显影响,获得的松弛参数要给出是在何种升降温速率下获得的。AG模型参数表现出很强的相关性,如果四个模型参数同时作为自由变量可能会得到不合理结果。通过和实验数据的对照,发现本研究的分析结果对于大致估算AG模型参数有一定指导意义。     

高强聚丙烯纺粘针刺土工布的耐久性能

为研究高强聚丙烯纺粘针刺土工布（HPP）的耐老化性能和耐化学腐蚀性能,采用热氧老化、酸与碱腐蚀液和纯水浸泡等实验,研究了不同温度和不同化学环境对其耐久性的影响,将其与普通聚丙烯土工布（PP）耐久性进行对比。结果表明：当样品在热氧化温度为110、120、130 ℃条件下处理25d 时,HPP 土工布质量保留率分别为 99.06%、98.85% 和 98.10%; PP 土工布质量保留率分别为98.89%、98.78% 和 97.78%;HPP 土工布纵向断裂强度保留率分别为75.00%、67.25% 和 64.71%,PP 土工布纵向断裂强度保留率分别为 72.15%、65.56% 和 54.00%。在 3 种不同液体处理下HPP 土工布的强度损失率均未超过5.00%,表明 HPP 土工布具有良好的耐腐蚀和耐水浸泡性。通过Arrhenius 定理拟合出 HPP 土工布热氧反应速率表达式,预测出 HPP 土工布使用 50a 后的强度保留率为27.30%。     

聚丙烯及聚酯纤维滤料耐紫外老化特性研究

以聚丙烯及聚酯纤维滤料为试验对象,采用UVC型紫外线辐射,进行人工老化试验,研究不同滤料紫外老化过程的性能变化.观察滤料形貌变化及纤维断裂情况,对老化过程中试样的拉伸断裂强度进行测试,并进行元素含量分析.同时,考察紫外线对箱体内的臭氧浓度的影响.测试结果表明:在一定辐射强度下,长时间紫外线辐射会导致滤料纤维的断裂降解,...     

航道用聚丙烯土工织物的老化性能研究

针对航道治理工程的使用环境开发了防老化聚丙烯复合土工织物。通过人工加速老化试验、大气自然老化试验、水下实地老化试验对所开发产品的老化性能进行研究和评价     

聚丙烯纺黏针刺土工布的力学和耐光氧老化性能

为提高聚丙烯纺黏针刺土工布产品质量,测试和分析聚丙烯纺黏针刺土工布的力学性能和耐光氧老化性能.结果 表明:在相同工艺条件下,聚丙烯纺黏针刺土工布的力学性能优于聚酯纺黏针刺土工布;聚丙烯纺黏针刺土工布抗拉强度、撕破强力、顶破强力和刺破强力均随着面密度的增大而提高;灰色母粒和UV 88抗老化母粒均可提高聚丙烯纺黏针刺土工布...     

Preparation and properties of polypropylene/clay nanocomposites for food packaging

Polypropylene (PP)/clay nanocomposites based on PP, organic clay (montmorillonite; MMT), and maleated polypropylene (MAPP) were prepared by melt compounding. The mechanical, thermal, morphological, and gas barrier properties of the resulting PP/clay nanocomposites were investigated at varying concentrations of the components for food packaging. The results revealed that the mechanical strengths, including tensile, flexural, and Izod impact strength, were increased for PP/clay nanocomposites compared to neat PP. The thermal properties showed a tendency for the melting and degradation temperatures to increase with the clay concentration. The effect of the compatibilizer was observed using scanning electron microscopy (SEM). The X-ray diffraction pattern of the nanocomposites revealed increased d-spacing of the MMT layers, indicating that the compatibility of neat PP and clay was improved by the addition of MAPP, and the intercalation and partial exfoliation of the layers. The use of clay increased the mobility distance of the gas molecules, leading to the oxygen permeability of neat PP being reduced by 26% to 55%.     

熔喷法聚丙烯过滤材料加工工艺参数对其性能的影响

介绍了熔喷法聚丙烯过滤材料生产的工艺原理及其过滤机理,调整加工工艺参数如空气压力、接收距离、平动次数等,讨论了各工艺参数对熔喷法聚丙烯过滤材料最终性能的影响。     

Evaluation of some of the physical properties of atmospheric plasma treated polypropylene fabric

In this study, atmospheric pressure plasma (APP) treatment was applied to polypropylene (PP) fabric with non‐polymerizing gases, such as air, argon, and nitrogen. Properties of the APP‐treated samples including low‐stress mechanical behavior, air permeability, water vapor permeability, and thermal characteristics were evaluated. Tensile and friction coefficient of the specimens were also measured. The changes in these properties are believed to be closely related to the inter‐fiber and inter‐yarn frictional force induced by the APP. The decrease in the air permeability of the APP‐treated PP fabric was probably because of the plasma action effect on change in fabric surface morphology, which was confirmed by scanning electron microscopy micrographs. The change in the thermal properties of the APP‐treated PP fabric was in good agreement with the earlier findings and can be attributed to the amount of air trapped between the yarns and fibers. This study suggests that the APP treatment can influence the final properties of the PP fabric, and also provides information for developing APP‐treated PP fabric for industrial use.     

黄酒陈酿过程中主要成分变化的研究

对不同陈酿时间的黄酒原酒进行了分析,结果表明,随黄酒酒龄的延长,黄酒主要理化指标酒精度、pH值、总酸、总糖等指标没有显著变化;总多酚在贮存期间呈下降趋势,尤其贮存前6年,降低率达到了27.6%,阿魏酸、槲皮素和原儿茶酸是引起多酚含量下降的主要原因.贮存期间,氨基酸尤其是苦味氨基酸也呈显著的下降趋势,这也是贮存期间黄酒苦涩味逐渐降低的主要原因.各种风味物质在贮存期间的变化规律不同,但总的趋势是醇和酸含量在降低,而酯类、醛类的含量在增加.5-甲基糠醛作为啤酒的老化指标,在该研究中含量从初始的3.06g/L上升到了113.34.g/L.     

Study of the optical properties of human hair

The optical properties of human hair were studied by photogoniometry. Starting from an optical model of hair, we developed a computerized method of decomposition of the goniophotometric curve. From our analysis we obtained structural parameters of the hair surface, average scale angle and cosmetic parameters like lustre and pigmentation. This method gave us new results in the following areas:
— the effects of bleaching on scale and internally reflected light;
— the study, from root to tip, of surface damage and hair pigmentation;
— the effects of stretching the hair on scale angle and lustre;
— the effects of sebum and dust on hair lustre.     

聚丙烯筒子纱染色工艺

针对聚丙烯纯纺筒子纱染色工艺中的松式络筒、前处理和染色等容易产生色差色花的关键工序,从筒子纱密度、前处理工艺、染色温度的控制等方面采取改进措施.结果表明,采用净洗剂和纯碱进行煮练清洗,用托拉司WW型分散染料在130°C进行染色,可获较好的匀染效果和色牢度.     

Diffusion behaviour of additives in polypropylene in correlation with polymer properties

The migration behaviour of polymer additives in 17 polypropylene (PP) samples is described. These samples cover the major types of PP used in food packaging. The diffusion coefficients of additives with relatively small molecular masses, M _r = 136 (limonene), as well as the migration of typical antioxidants used in PP up to M _r = 1178 (IRGANOX 1010), were measured at different temperatures. In addition, the diffusion data and percentages of xylene-soluble fractions were correlated. This enables a prediction of the migration behaviour of a PP sample by testing its ‘isotactic index’ with xylene. The results clearly indicate that PP can be subdivided, from the migration point of view, into the monophasic homopolymer (h-PP), the monophasic random copolymer (r-PP), and the heterophasic copolymer (heco-PP). The diffusion coefficients for r-PP are at least one order of magnitude higher than those of h-PP and comparable with the values for heco-PP. Upper limits for the diffusion values can be calculated based on the safety margin required by consumer protection laws.     

An investigation on the effects of heat-setting process on the properties of polypropylene bulked continuous filament yarns

Heat-set bulked continuous filament (BCF) polypropylene yarns constitute one of the most important pile yarns used in the production of machine-woven carpets. As carpets made from non-heat-set BCF polypropylene yarns lack resiliency and loss of appearance, heat setting of BCF yarns has proved to be very useful in overcoming these deficiencies. This work aimed to investigate the effects of dry steam heat setting on the structure, properties and structural–property relationship of industrially produced heat-set BCF polypropylene yarns. It was ascertained that while tenacity, initial modulus, bending rigidity, crimp contraction and shrinkage decrease as a result of heat setting process, there is an increase in the yarn linear density. Because of these mechanical changes, the resiliency of BCF polypropylene yarns is positively affected by heat-setting process, and as a result, a better wear and look for the carpet pile yarns. Changes in mechanical properties result from microstructural changes, namely, recrystallization induced by heat-setting process. Recrystallization leads to a higher overall crystallinity, with a higher number of smaller crystallites giving improved orientation. Lower initial modulus leads to a lower flexural rigidity or stiffness, thus giving rise to a better resiliency of heat-set BCF polypropylene yarns. This is related to the formation of smaller size crystallites in spite of the higher degree of crystallinity.     

大米淀粉-甘油单棕榈酸酯复合物的制备及其老化性质研究

目的 为了减缓大米淀粉在加工过程中的老化,延长大米淀粉制品的货架期,制备具有抗老化效果的大米淀粉-甘油单棕榈酸酯复合物。方法 以复合指数为评价指标,通过单因素及响应面试验对复合物制备工艺中甘油单棕榈酸酯添加量、复合温度和复合时间进行优化,对大米淀粉及最优条件下制备的大米淀粉-甘油单棕榈酸酯复合物的溶解度、膨胀度、冻融稳定性和糊化特性进行了测定。结果 试验得到的最佳制备工艺参数为：甘油单棕榈酸酯添加量5%、复合温度80 ℃、复合时间30 min。同时与大米淀粉相比,大米淀粉-甘油单棕榈酸酯复合物的溶解度、膨胀度、冻融稳定性、糊化特征参数均呈下降趋势,其中冻融后复合物的析水率下降了35.62%。 X衍射结果表明,复合物的晶型由A型向V型转变。结论 大米淀粉-甘油单棕榈酸酯复合在一定程度上可延缓淀粉老化。