聚丙烯的透明改性

以聚丙烯粉料为研究对象,以商品透明成核剂和硬脂酸钙以及抗氧剂1010等助剂为原料,通过熔融共混法制备了透明聚丙烯。通过光透过率测试、X射线衍射分析、偏光显微镜观察、力学性能测试等手段对所得聚丙烯进行了分析表征。结果表明,随着成核剂的加入,聚丙烯透明性先增加而后下降,最佳加入量为0．25％;成核剂用量的增加,球晶颗粒尺寸减小;加入成核剂,聚丙烯力学性能也明显提高。     

聚丙烯高透明高流动专用树脂M2000E开发

论述了聚丙烯高透明高流动专用料M2000E透明成核剂筛选,以及透明成核剂对聚丙烯光学和力学性能的影响;进行了各种高透明聚丙烯产品基本性能以及乙烯含量测试,借助DSC、GPC等分析方法对国内外同类产品结构剖析,试验结果表明,高透明高流动M2000E产品与同类产品相比,透明性以及力学性能较好。     

α-成核剂对均聚聚丙烯性能的影响

考察了几种α-成核剂对聚丙烯性能的影响,选取改性性能较好的成核剂,分析了该成核剂对聚丙烯力学性能和结晶性能的影响。结果表明:随着成核剂用量的增加,聚丙烯的力学性能先升高再降低;加入成核剂可明显提高聚丙烯的结晶温度,加快结晶速率,晶粒尺寸明显变小。     

不同晶型成核剂在聚丙烯改性中的应用

本文介绍了聚丙烯成核剂的种类及其不同晶型成核剂在聚丙烯改性中的应用。重点介绍了山梨醇苄叉衍生物类成核剂在聚丙烯透明改性中的应用及通过实验对比研究分析了α、β两大晶型成核剂对聚丙烯力学性能及加工性能的影响。     

挤出温度对α成核聚丙烯透光性和力学性能的影响

向均聚聚丙烯(iPP)中添加α成核剂制备透明聚丙烯时,挤出过程设置不同挤出温度,以考察挤出温度对样品透光性能和力学性能影响的机理。测试了透光率和力学性能。结果表明,当挤出温度为230℃时可以获得透光率最佳的样品,这是由于温度高时α成核剂溶解度变大,成核密度变大,晶体尺寸减小所致;拉伸强度提高,断裂伸长率和冲击强度有所降低。     

成核剂对聚丙烯部分力学性能的改善分析

在聚丙烯中以比例2%分别加入有机磷酸酯类的成核剂611,612,613,NA-11和0629C-3,观察了样品脆断面的结构情况,测试了成核剂加入前后样品力学性能的改变,并就改变的原因进行了分析;同时,也对在样品中加入1%成核剂0629C-3的结果与加入2%的结果进行了比较。     

四羧酸酞菁成核剂对聚丙烯性能的影响

采用偏光显微镜(PLM)、差示扫描量热法(DSC)、力学性能测试研究四羧酸酞菁成核剂对聚丙烯结晶形态、结晶性能、力学性能的影响,以及成核剂的最佳添加量。结果表明,四羧酸酞菁的加入可以增加聚丙烯的结晶速度,减小结晶尺寸,使球晶表面细化,球晶结构分布均匀,同时聚丙烯的力学性能得到提升。当成核剂的添加量为0.3%,对聚丙烯的性能提升达到最佳。与聚丙烯相比,改性聚丙烯的冲击强度、拉伸强度、弯曲强度分别提升10.2%、19.4%、23.3%。     

透明PP片材专用树脂的研制

以均聚聚丙烯(PP)为基础树脂,通过加入成核剂生产透明PP片材专用树脂。探讨了成核剂的加入量及片材加工温度对片材透明性能的影响,确定PP片材最佳加工温度为230℃。成核剂的加入使PP的结晶度由 44．1％提高到51．4％,结晶温度、熔点等均有不同程度的提高。     

注塑级透明聚丙烯专用料的研制与生产

以均聚聚丙烯(PP)为基体树脂,通过添加成核剂制备了注塑级透明PP专用料。成核剂的加入．不但改善了PP的光学性能,而且提高了PP的刚性,在某种程度上改善了其加工性能。为降低生产成本和提高透明PP的性能,研制了复配成核剂体系,添加该成核剂生产的透明PP的各项性能均达到技术指标;并讨论了加工温度和树脂熔体流动速率对透明PP光学性能的影响。     

β成核剂协同增韧PP/POE复合材料性能研究

将β成核剂加入到PP/POE(聚丙烯/聚烯烃弹性体)体系中,进行熔融共混,经成型加工制备标准样条,测试样条的拉伸性能、冲击性能、结晶性能以及热力学性能。研究结果表明:β成核剂的加入可有效改善PP/POE力学性能最佳;β成核剂的加入可有效改善PP/POE体系的结晶情况,随着POE在体系中含量的增加,结晶度呈现逐渐减小的趋势。     

透明聚丙烯性能的研究

采用偏光显微镜（ＰＬＭ）、差示扫描量热仪（ＤＳＣ）、毛细管流变仪和拉伸试验机对透明聚丙烯（ＰＰ）的结晶形态、热学、流变性、力学性能进行了研究。结果表明：与普通聚丙烯相比,透明聚丙烯不但光学性能得到改善,其他性能也有不同程度的提高,综合性能优于普通聚丙烯     

竹纤维增强PP复合材料的研究

介绍了竹纤维增强聚丙烯(PP)复合材料的性能,初步探讨了竹纤维的处理、未处理以及纤维含量对增强PP的力学性能的影响因素。实验证明:与PP材料相比,添加竹纤维可使复合材料的力学性能有不同程度的改善,特别是对复合材料的冲击强度、拉伸强度及断裂伸长率影响较明显。     

Effect of Organomodified Ni-Al Layered Double Hydroxide (OLDH) on the Properties of Polypropylene (PP)/LDH Nanocomposites

This work addresses the effect of organomodified layer double hydroxide (OLDH) on the properties of PP/LDH nanocomposites prepared by melt intercalation method using a single screw extruder with maleic anhydride grafted polypropylene (PP-g-MA) as a compatibilizer. For this, Ni-Al LDH was first prepared by the co-precipitation method at constant pH using their nitrate salts. The above synthesized pristine LDH was organically modified using sodium dodecyl sulphate (SDS) by the regeneration method. The structural and thermal properties of LDH and PP nanocomposites were performed by X-ray diffraction (XRD), FTIR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The influence of LDH loading on the mechanical and thermal properties of the nanocomposite was also investigated. The XRD results confirmed the formation of exfoliated PP/LDH nanocomposites. PP/LDH nanocomposites exhibited enhanced thermal stability relative to the pure PP. When 10% weight loss was selected as a point of comparison, the decomposition temperature of PP/LDH (5 wt%) nanocomposite was 15.3°C higher than that of pure PP. The DSC result indicated an increase in crystallization and melting temperature of the PP/LDH nanocomposites compared to pure PP. Overall, the mechanical properties of the PP/LDH nanocomposites increased with an increase in the LDH content. The maximum improvement of tensile strength, Young's modulus, flexural strength, and flexural modulus for the PP/LDH nanocomposite was found to be 11, 22.5, 28, and 22%, respectively, over neat PP. For comparison purposes, a nanocomposite with 5 wt% modified bentonite (PP/B5) was also prepared under the same operating condition and there was no significant improvement in mechanical properties (tensile strength and modulus).     

纳米ZnO/PP及ZnO/CaCO_3/PP复合材料的性能研究

纳米氧化锌(ZnO)与聚丙烯(PP)通过熔融共挤制得了ZnO/PP纳米复合材料.研究了ZnO/PP纳米复合材料的力学、流变学性能与纳米ZnO添加量之间的关系;同时制备了ZnO/CaCO3/PP三元纳米复合材料并对其进行了机械性能和制备成本分析.结果表明,ZnO/PP纳米复合材料的熔体质量流动速率较纯PP有较大程度的提高;纳米CaCO3的加入不但可以降低生产成本,而且可以显著改善体系的冲击韧性;材料的拉伸破坏属于韧性断裂过程.     

Studies on morphology,mechanical, thermal,and dynamic mechanical behavior of extrusion blended polypropylene and thermotropic liquid crystalline polymer in presence of compatibilizer

Polypropylene was melt blended in a single screw extruder with thermo tropic Vectra B‐950 liquid crystalline polymer (copolyester amide) in different proportions in presence of 2% of EAA, ethylene‐acrylic acid copolymer (based on PP) as a compatibilizer. The mechanical properties of such compatibilized blends were evaluated and compared in respect of their Young's Modulii, Ultimate tensile strength, percent elongation at break, and toughness to those of Pure PP. The Morphology was studied by using a polarizing light microscope (PLM) and Scanning electron microscope (SEM). The Thermal characterization of these blends were carried out by differential scanning calorimeter (DSC).The mechanical properties under dynamic conditions of such compatibilized blends and pure PP were studied by dynamic mechanical analyzer (DMA). Mechanical analysis (Tensile properties) of the compatibilized blends displayed improvements in Modulii and ultimate tensile strength (UTS) of PP matrix with the incorporation of 2–10% of LCP incorporation. The development of fine fibrillar morphology in the compatibilized PP/LCP blends had large influence on the mechanical properties. Differential scanning calorimeter (DSC) studies indicated no remarkable changes in the crystalline melting temperature of the blends with respect to that of pure PP. However, an increase in the softening range of the blends over that of PP was observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚丙烯/n-SiO2复合材料的制备与性能研究

采用熔融共混法制备了PP/纳米SiO2复合材料,并通过力学性能测试、DSC分析以及材料断面形貌分析等手段,对增强增韧效果进行了研究。结果表明,加入纳米SiO2能提高了PP的结晶速率,使结晶度增大。当纳米SiO2的质量分数为2%时可使PP/nSiO2复合材料的缺口冲击强度提高2倍,拉伸强度稍微下降。     

纳米钠基蒙脱土填充改性聚丙烯

采用熔融法把纳米钠基蒙脱土填充到聚丙烯中。研究了纳米钠基蒙脱土对聚丙烯的力学性能的影响。结果表明：添加适量的纳米钠基蒙脱土能够显著改善聚丙烯的力学性能;与纯聚丙烯相比,当纳米钠基蒙脱土含量达到3％（wt）-5％㈩时,冲击强度能增加30％以上,断裂伸长率增加了16％以上,拉伸强度增加了27％以上,弹性模量降低了17％以上。     

聚丙烯/膨胀石墨/碳纤维导热复合材料

研究了聚丙烯(PP)/膨胀石墨(EG)/碳纤维(CF)复合材料的导热、力学以及加工性能.研究发现:当膨胀石墨的质量含量达到20％时,热导率是纯聚丙烯的2倍,但熔体流动性能有所下降;添加1％的聚乙烯蜡可以明显改善体系的熔体流动性能;将膨胀石墨与5％的碳纤维杂化使用,热导率达0.91 W·m-1K-1,是纯聚丙烯的5倍,熔体指数达到1.72 g/10 min,同时该复合材料具有较好的力学性能.     

Extrusion of ultrahigh molecular weight polyethylene under ultrasonic vibration field

The effects of polypropylene (PP) and ultrasonic irradiation on the processing and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) are studied. The results show that PP can effectively improve the fluidity and mechanical properties of UHMWPE. The Izod notched impact strength increases from 92 kJ/m² for pure UHMWPE to 109.2 kJ/m² for the blend of UHMWPE with 10 wt % PP. The Young's modulus increases from 528 MPa for pure UHMWPE to 1128 MPa when 25 wt % PP is contained in the blend, and the yield strength also rises when PP is added. The application of ultrasonic vibrations during extrusion can prominently decrease the die pressure and apparent viscosity of the melt, thus increasing the output of extrudate. An appropriate ultrasonic intensity and irradiation time can further promote the mechanical properties, while an overdose of irradiation destroys them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2628–2632, 2003     

ANN方法分析预测聚丙烯材料的力学性能

利用Ｂ－Ｐ人工神经网络（ＡＪＮＮ）对聚丙烯（ＰＰ）的力学性能进行了分析和预测。首先将ＰＰ材料接纯ＰＰ、共混和增韧及填充和增强ＰＰ等进行分类,并根据这些数据的特点建立Ｂ－Ｐ网络,然后用各类ＰＰ材料的组成和力学性能数据对网络进行学习训练,最后用“未知样品”的数据对网络进行验证。结果表明,所建立的网络能反映ＰＰ的力学性能特性,预测有一定的准确性,但不同类别的材料预测准确性不同。