Effect of Oleic Acid-modified Nano-CaCO3 on the Crystallization Behavior and Mechanical Properties of Polypropylene

Oleic acid (OA)-modified CaCO3 nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene (PP) was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystallization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the formation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PP/CaCO3 nanocomposites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical properties of PP. In comparison with PP, the impact strength of PP/CaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%.

Effect of Oleic Acid-modified Nano-CaCO_3 on the Crystallization Behavior and Mechanical Properties of Polypropylene

Oleic acid OA-modified CaCO3 nanoparticles were prepared using surface modification method. In- frared spectroscopy IR was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene PP was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystal- lization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the for- mation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PPCaCO3 nanocompo- sites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical proper- ties of PP. In comparison with PP, the impact strength of PPCaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%.

共混工艺对PP/EVA/nano-CaCO_3三元复合材料性能的影响

采用两种共混工艺分别制备出以分散和包覆结构为主的PP/EVA/nano-CaCO3三元复合材料FCa3和BCa3,通过对三元复合材料力学性能的测试和热性能的表征,以及对微观形貌和冲击断面的观察分析,讨论了共混工艺对三元复合材料性能与结构的影响。实验结果表明,BCa3的屈服强度,杨氏模量,维卡软化温度均高于FCa3,而FCa3的屈服应变,断裂伸长率和冲击韧性却大于BCa3,揭示出EVA-nano-CaCO3包覆结构比分散结构具有较好的增强作用。

The Effect of Inorganic Nanoadditives on the Thermal, Mechanical and UV Radiation Barrier Properties of Polypropylene Fibres

The objective of this study of modified polypropylene (PP) fibres using nanoadditives (nano-CaCO3 and Cloisite 30B) was to determine the influence of these additives on thermal and mechanical properties, but especially on the barrier properties of the nanocomposite fibres against UV radiation. The DSC data obtained from measurements of PP/CaCO3 or PP/C30B nanocomposite fibres were used for determination of the constants n and K of the Avrami equation and in the estimation of other thermal properties of the fibres, such as their crystallization half-time t1/2, rate of crystallization t1/2, the necessary time for maximum crystallization tmax and free energy per unit area of surface in the lamella perpen-dicular to the axis of a high-molecular chain se. The nano-CaCO3 or Closite 30B fillers (pre-treated separately in three different solvents: glycerine, acetone and water) did not influence the melting temperatures but caused an increase in PP crystallization temperatures in comparison with the pure PP fibres. The pre-treatments of nanoadditives resulted in increase of n, K, t1/2 values and decrease of t1/2, tmax as well as the values of free surface energies per unit area of the modified PP fibres. There was also observed a decrease in the mechanical properties, however, there was an increase of barrier properties against UV radiation of nanocomposite PP fibres in comparison with neat PP fibres, which was one of the main objectives of the study.

改性纳米CaCO_3/HDPE复合材料性能的研究

在 HDPE中加入高分子偶联剂改性的纳米 Ca CO3 ,测试了复合材料的力学性能和流变性能。发现高分子偶联剂的加入改善了无机粒子和聚合物间的结合 ,促进了无机粒子在体系中的均匀分散 ,使体系的力学性能上升 ,高分子偶联剂的最佳使用量 (质量分数 )是 1% ;纳米 Ca CO3 的加入减小了体系的弹性 ,增加了刚性 ,改善了材料的挤出特性 ,对体系的流变性能没有产生大的影响。

PP/EVA/纳米CaCO_3复合体系力学性能的研究

采用双螺杆熔融共混法,以两种混合方式制备了聚丙烯(PP)/乙烯醋酸乙烯酯(EVA)/纳米碳酸钙(CaCO3)复合材料。研究了纳米CaCO3用量对复合材料力学性能的影响。研究结果表明:经表面处理的纳米CaCO3粒子的加入对复合材料有明显的增韧效果。两种不同混合方式最佳纳米CaCO3用量均为3%左右。采取先将PP与EVA共混挤出后再与纳米CaCO3进行混合挤出的两步法工艺,制得的复合材料的综合性能较优。

HDPE/CaCO_3复合材料的力学和热性能

应用Ｉｎｓｔｒｏｎ 材料试验机和Ｃｅａｓｔ 冲击试验机于室温下测量碳酸钙填充高密度聚乙烯（ＨＤＰＥ） 复合材料。随着填料质量分数（Φ） 的增加，试样的拉伸模量和拉伸断裂能呈非线性增大；而拉伸屈服应力、拉伸强度和冲击断裂能则仅在Φ＝ １０ ％ 时稍大于未填充的ＨＤＰＥ。热重分析实验结果表明，试样的热分解温度随着Φ的增加而呈非线性函数形式增大。

CaCO_3对EVA热熔胶力学性能的影响

研究了CaCO3 对EVA热熔胶软化点、剥离强度。

A-CaCO_3及HDPE-g-MAH对HDPE复合材料性能的影响

采用熔融混炼法制备了活性碳酸钙(A-CaCO3)填充高密度聚乙烯(HDPE)复合材料。研究了A-CaCO3和马来酸酐接枝HDPE(HDPE-g-MAH)对复合材料力学性能、结晶性能的影响;并采用SEM对复合材料的微观形貌进行了观察。研究结果表明:A-CaCO3对HDPE/A-CaCO3复合材料的拉伸强度和弯曲强度影响不大,但能提高复合材料的冲击强度和结晶度;HDPE-g-MAH的加入能够显著改善A-CaCO3与基体HDPE之间的界面相容性,提高HDPE/HDPE-g-MAH/A-CaCO3复合材料的拉伸强度和结晶度,但降低了复合材料的冲击强度。