Journal of South China University of Technology (Natural Science Edition) ›› 2011, Vol. 39 ›› Issue (6): 77-83.doi: 10.3969/j.issn.1000-565X.2011.06.014

• Materials Science & Technology • Previous Articles     Next Articles

Relationship Between Mechanical Properties and Crystalline Structure of PPR/iPP Blends Modified with β-Nucleator

Zhu Ya-ming1  Liu Shu-mei1  Jiang Wen-zhen2  Zhou Yan-hui1  Zhao Jian-qing1   

  1. 1. School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China; 2. Guangzhou Honsea Chemistry Corporation,Ltd.,Guangzhou 510620,Guangdong,China
  • Received:2010-11-05 Revised:2010-12-16 Online:2011-06-25 Published:2011-05-06
  • Contact: 刘述梅(1968-)，女，博士，副教授，主要从事有机硅合成、高分子材料改性等的研究． E-mail: liusm@scut．edu．cn E-mail:psymzhu@ scut.edu.cn
  • About author:朱亚明(1978-) ，男，工程师，主要从事高分子材料改性研究．
  • Supported by:

    广东省教育部产学研结合项目－基地建设专项( 2009B090200025 ) ; 广东省教育部产学研结合项目( 2010B090400150)

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Abstract:

In this paper,the relationship between the mechanical properties and the crystalline structure of propylene random copolymer ( PPR) /isotactic polypropylene ( iPP) blends modified by a rare earth complex ( β-nucleator) was investigated by means of DSC and XRD. When the dosage of β-nucleator is kept at 0. 05%,it is found that ( 1) the impact strengths of PPR,PPR/iPP( 70 /30,50 /50 and 30 /70 in mass ratio,respectively) blends and
iPP increase from 42. 7,33. 7,14. 5,8. 3 and 5. 1 kJ /m2 to 87. 8,63. 4,29. 3,13. 9 and 8. 2 kJ /m2,respectively,while the tensile strengths all decrease by less than 10%; ( 2) the melting temperature of PPR/iPP ( 70 /30 in mass ratio) blend decreases from 161. 9 ℃ to 149. 8 ℃ and the relative content of β-form crystal increases from 45. 3% to 53. 1%,which reveals a remarkable nucleating promotion to β-form crystal; and ( 3) there exist typical ductile fractures in the impact-fractured sections of the blend,which is verified by the SEM photographs. Moreover,when the dosage of β-nucleator increases to 0. 20%,the melting temperature of the blend and the relative content of β-form crystal respectively reach 159. 8℃ and 45. 1%,and the nucleation to β-form crystal of the blend weakens,thus resulting in a decrease in the impact toughness.

Key words: polypropylene, blending, toughening, nucleation, crystal form