影响几种树脂粒料产品黄色指数测定因素的研究

通过对聚乙烯、聚丙烯树脂粒料产品黄色指数测定中色差仪预热时间、标准板校正时间间隔、样品量、样品杯杯盖和平均值测量时测量次数等因素对测定结果影响的讨论,确定了黄色指数测定实验的最佳实验条件,并且得到比较好的重复性和再现性。     

聚丙烯粉料乙烯含量测定影响因素研究

利用外商提供的分析方法和一系列标样样片,建立了无规和抗冲共聚聚丙烯中乙烯含量测定的工作曲线,由于聚丙烯粉料样品结构与性质的不稳定性和不均匀性,决定了实际粉料样品乙烯含量在测试处理上往往不能完全与建立标线处理上的一致。通过选取不同牌号乙丙共聚聚丙烯粉料样品,着重试验分析了热压制样中冷却方式、抗氧剂、样品粒径对粉料乙烯含量测定结果的影响。结果表明,热压制样中冷却方式对粉料乙烯含量的测定结果形成了较为明显的影响;同样粉料样品中是否添加抗氧剂及所加抗氧剂的种类对测定结果也构成了很大程度的影响;另外,粉料样品粒径对乙烯含量的测定结果形成了显著的影响。     

合成树脂颜色外观测试标准及方法研究

通过对合成树脂产品颜色外观测试方法的研究,参照方法标准HG/T3862-2006《塑料黄色指数测定方法》,测试时在样品上加盖白板(以白板为背景),在相同的测量光孔直径条件下,测试结果扣除白板背景对黄色指数的贡献。试验表明,相同样品使用不同测试仪器,在测量光孔直径?25~?30 mm之间测试的结果扣除白板黄色指数,所得的结果吻合,为该方法标准应用更具有可操作性提供了依据。     

乙丙橡胶色度检测的影响因素分析

采用不同的操作条件,分析样品厚度、背景、入射光模式、样品透明度等因素对测定乙丙橡胶色度值的影响。结果表明,实验测得乙丙橡胶黄色指数(YI)和在日光照射下观察到的黄色程度能较好地吻合,因而能用于评价乙丙橡胶外观色度。     

受阻胺光稳定剂与紫外吸收剂协同改进ABS树脂抗光氧老化性能研究

对比研究了不同类型的紫外光吸收剂(UVA)与受阻胺光稳定剂(HALS)光稳定剂协同改善ABS树脂抗光氧老化性能的效果。评价了ABS树脂样品在自然光老化条件下,黄色指数、聚丁二烯(PB)橡胶相1,4反式结构中C-H的IR吸收指数和光氧化产生的C=O的IR吸收指数、洛氏硬度及光泽度随时间变化情况。结果表明,HALS光稳定剂与草酰胺类UVA表现出较理想的协同作用,可以使ABS树脂在自然光老化6个月后黄色指数保持稳定不变。     

191#不饱和聚酯／玻璃钢人工加速老化研究

对191#不饱和聚酯及其玻璃钢进行了人工热氧加速老化和人工氙灯加速老化试验.用显微镜观察了试样的外观形貌,用光泽度仪测试了试样光泽度,色差计测定了试样表面的黄色指数,对聚酯进行了FT-IR和DMA分析,测试了聚酯和玻璃钢的拉伸强度和弯曲强度.试验表明,随着加速老化时间的延长,试样表面出现光泽度降低、泛黄、龟裂等现象,且失光率、泛黄程度、裂纹长度和力学性能的变化与人工老化方式相关,DMA分析证实聚酯氙灯老化90天后Tg由84℃上升到88℃,老化240天后为83℃,聚酯老化后的储存模量也有一定程度的下降;而弯曲强度、拉伸强度则出现先上升后下降趋势;191#聚酯/玻璃钢对氙灯老化更为敏感.     

SEBS在低光泽POM材料的应用及性能研究

为开发低光泽POM材料并研究材料力学性能以及结构,采用双螺杆挤出机制备了POM/SEBS共混物,并研究了SEBS添加量对共混体系的力学性能以及表面光泽度的影响。结果表明,随着SEBS添加量的增加,材料的拉伸强度、弯曲强度和弯曲模量、冲击强度明显降低,断裂伸长率上升,同时材料表面的光泽度也明显下降。通过光学显微镜观察共混体系的表面形貌,SEBS在POM基体表面形成微细凹凸。     

硫化橡胶在热氧化过程中光泽度变化初探

应用UGV——4D型数字变角光泽计测定了两种硫化橡胶经热氧老化后的光泽度变化,将测定结果进行回归分析,发现光泽度变化率随老化时间的延长呈抛物线规律变化。实验还证实温度对光泽度变化有较大影响。温度愈高,光泽度升高所需的时间愈短,如试样1在90℃和110℃条件下老化9小时,光泽度就升高10％,而在50℃和70℃条件下光泽度升高10％约需170小时。同时还可看到,不同配方的硫化橡胶光泽度变化率不同。     

ABS/AS复合材料的制备及其在乒乓球中的应用

制备了丙烯腈-丁二烯-苯乙烯树脂/苯乙烯-丙烯腈共聚物(ABS/AS)复合材料,研究了AS的用量对复合材料力学性能、耐热性、表面光泽度及耐磨性的影响。结果表明:随着AS用量的增加,复合材料的邵氏硬度D和冲击强度逐渐增大,维卡软化点逐渐升高,接近于AS的维卡软化点110oC;AS的加入改善了样品的表面光泽度,在AS用量为15%时达到最大值,继续添加AS,样品的表面光泽度下降。随着AS用量的增加,ABS/AS复合材料的耐磨性有所改善。SEM结果表明,AS可以与ABS形成较好的黏合作用,摩擦外力对于材料表面的形貌影响较小。     

浅谈影响高锰酸盐指数测定的三个因素

高锰酸盐指数作为反映水体中有机及无机可氧化物质污染的常用指标,也是地表水监测的一个重要指标,但它是一个相对的条件性指标,其测定结果受条件的影响较大。通过试验,考察研究了不同种类的实验室用水、样品的不同保存条件以及K值等因素对高锰酸盐指数测定结果的影响,以提高高锰酸盐指数测定结果的准确性,保证实验分析工作的精密性和科学性。     

漆膜厚度对面漆表观性能影响的研究

重点研究了不同色浆层厚度和清漆厚度对面漆粗糙度、光泽、雾影和平展度值的影响,并将研究成果应用于实际生产的过程中。     

城轨车辆用聚氨酯半光漆光泽稳定性研究

以丙烯酸树脂为基料,制得了适合城轨车辆使用的聚氨酯半光漆.研究了不同丙烯酸树脂、不同CAB助剂、不同涂膜干燥方式及不同涂膜厚度对半光漆光泽稳定性的影响.通过SEM和IR等检测手段对涂料性能进行了表征.结果表明,当选用某高羟值树脂和低羟值树脂搭配使用时,半光漆具有较好的光泽稳定性,当助剂CAB381和CAB551搭配使用时,此时消光粉有最佳的定向效果,当采用常温晾1h、60℃烘干1h的干燥工艺及涂膜厚度控制在40～60μm时,此时涂料光泽波动最小.     

Degumming of ramie: the role of the individual constituents of the gummy material

The stepwise removal of the components of gummy material found on ramie fibres was used to determine the effects of the individual constituents on the whiteness and yellowness indices of the fibres. The main components were found to be hemicellulose, pectin and lignin and these had the greatest effect on the whiteness and yellowness indices. A spectroscopic method for assessing the hemicellulose and pectin content of the degumming bath was investigated and found to be comparable to the results of chemical analysis. The spectroscopic method was used to study the removal of hemicellulose and pectin continuously during degumming, and the data obtained were used to calculate rate constants for the degumming process.     

Coatings prepared from waterborne polyurethane dispersions obtained with polycarbonates of 1,6-hexanediol of different molecular weights

Waterborne polyurethane dispersions (PUDs) were synthesized with polycarbonates of 1,6-hexanediol of different molecular weight (500–3000 Da) and their properties, adhesion (Hatch adhesion) and coatings on stainless steel properties (Pencil hardness, Persoz hardness, gloss at 60°, chemical resistance, yellowness index) were characterized. The hatch adhesion of the polyurethane coatings to stainless steel was very good and decreased slightly by increasing the molecular weight of the polycarbonate of 1,6-hexanediol. Both the Pencil and Persoz hardness values of the coatings increased by increasing the hard segments content in the polyurethane, i.e. by decreasing the molecular weight of the polycarbonate of 1,6-hexanediol, whereas the gloss and the yellowness index were lower for the coatings obtained with the polycarbonate of 1,6-hexanediol of molecular weight of 500 Da. Very good chemical resistance against ethanol for all polyurethane coatings on stainless steel plates was obtained but for long time of ethanol in contact with the coating surface the chemical resistance decreased, more markedly for the polyurethane coating obtained with the polycarbonate of 1,6-hexanediol of higher molecular weight. In summary, the segmented structure of the waterborne polyurethane dispersion determined the properties of the polyurethane coatings obtained from them.     

191～#不饱和聚酯树脂西部曝晒和人工加速老化的研究

对191#不饱和聚酯树脂进行了自然曝晒老化、人工热氧加速老化及人工氙灯加速老化试验,并对老化前后试样的外观形貌、光泽度、黄色指数、拉伸强度和弯曲强度进行了研究。实验结果表明,随着加速老化的不断进行,试样表面会出现泛黄、失光率增大和裂纹等现象,强度呈先增后降的趋势,弯曲强度由20 MPa(未老化时)增至最大值40 MPa(热氧老化60 d或氙灯老化45 d),拉伸强度由113 MPa(未老化时)增至最大值125 MPa(氙灯老化30 d)和128 MPa(热氧老化60 d);老化方式不同,老化前后试样的性能变化也不相同,即失光率对热氧老化更敏感、强度对紫外光老化更敏感;西部曝晒180 d,不饱和聚酯树脂仍处于后固化阶段,但强度已开始下降,下降程度与曝晒地区有关,变化最明显的是新疆尉犁地区,弯曲强度由最大值40 MPa(自然曝晒120 d)降低至35 MPa(自然曝晒180 d)。     

高温高压撞击混合及手工刮涂对聚脲涂层性能的影响

研究了高温高压撞击混合喷涂工艺制备的聚脲涂层(S样)和室温常压手工刮涂工艺制备的聚脲涂层(K样)的光泽、力学性能和微观形貌,分析了高温高压撞击混合喷涂及手工刮涂2种成型方式对聚脲涂层性能的影响规律。力学性能研究结果表明,涂层1～7 d力学强度增长迅速,7 d的力学强度可达到最终的80%左右,7 d后缓慢增长。S样的拉伸强度为22.11 MPa,断裂伸长率为485.99%;K样的拉伸强度为10.21 MPa,断裂伸长率为85.65%;S样力学性能显著强于K样。S样第1天邵氏硬度为A82,最终为A88;K样第1天为A55,最终为A68,硬度发展很快;表明聚脲涂层在早期硬段微区有序程度及硬段和软段两相混合程度较高。微观形貌研究显示,S样表面平整致密,K样表面存在气泡,缺陷较多,很好地佐证了S样的光泽和力学性能远远优于K样的实验结果。     

高光泽聚丙烯的研制

本研究着重讨论了成核剂、填料对高光泽聚丙烯的影响。实验表明,对聚丙烯增光效果最好的是芳基磷酸酯盐,其最佳质量分数为0．3％。各种无机填料的加入,对聚丙烯的光泽度都有影响,影响最小的是硫酸钡。在高光泽聚丙烯中,硫酸钡用量增加,材料的光泽度、弯曲强度、拉伸强度均下降,冲击强度和熔融指数上升。     

The effect of clear coat and basecoat interdiffusion on the appearance of automotive coating system

In this study, the possible effect of clear coat and basecoat interdiffusion on final appearance of the coating system is examined. The clear coat was applied at different thicknesses wet on wet on the basecoat. The orientation of aluminum flakes was evaluated by the orientation distribution and the flop index measured by the goniospectrophotometer. The gloss, haze, specular reflectance, distinctness of image and orange peel attributes were measured by the goniophotometer and the orange peel analyzer, respectively. The obtained results indicated that the clear coat thickness had no influence on the orientation distribution and the flop index, while the other measured appearance attributes were under influence of clear coat thickness. Optimal appearance attributes were achieved at 75.3 ± 1.8 μm of the clear coat. In addition, the texture analysis was performed on the images of the coatings. No variation in texture was found by increasing the clear coat thickness. Based on the appearance measurement results, it seems that interdiffusion of the basecoat and clear coat has negligible impact on the appearance of the coating system.     

The durability of paint films containing titanium dioxide — Contraction,erosion and clear layer theories

For gloss paint films containing titanium dioxide, evidence fundamental to the development of weathering theories, including weight loss, thickness loss and electron microscope examination of weathered surfaces, especially for the stages before chalking, is critically reviewed and discussed. It is concluded that the published data, considered as a whole, cannot be explained by erosion of the surface, but can easily be interpreted in terms of a model based on appreciable degradation beneath the surface, decreasing with depth depending on the penetration of u.v. radiation. This results in differential contraction of the surface layers and an increasing surface pigment concentration.Various ‘clear layer’ theories are also discussed and distinguished by the thickness of the clear layer proposed. It is concluded that there is no convincing evidence that distinct uniform pigment-free layers exist in normal air-drying gloss paints. Even if clear layers ≈ 0.2 – 0.5 μm thick were present, durability results could still not be explained by erosion. Effects of pigment volume concentration on the specular gloss of alkyd paints at various wavelengths, which have been interpreted in terms of ‘clear layers’ and optical interference, can be much more satisfactorily explained by alternative theories (based on gloss reduction at particular wavelengths due to surface micro-defects, and gloss enhancement at higher PVC's due to refractive index effects).Some implications of contraction are considered. Because erosion has been assumed in all visualisations of the weathering process previously published, sketches illustrating the effect of a number of variables on the contraction model are included.     

Alkylated phenolic antioxidants for paints

Summary  Polymeric antioxidants based on p-cumyl phenol formaldehyde resin (PCPF), p-nonyl phenol formaldehyde (PNPF) and p-octyl phenol formaldehyde (POPF) were prepared by condensation reaction of respective phenols with formaldehyde in presence of an acid catalyst. The reactions were monitored by TLC and the melting point of the products was determined by open capillary method. Stabilising the action of PCPF, PNPF for protecting paint against thermal oxidation was tested using a QUV weatherometer. The effect of exposure on the properties of paints such as gloss, whiteness and yellowness were evaluated. Results show that paints containing these new polymeric antioxidants possess better stabilising effects against photo-oxidation than those employed in standard paints available in the market.