Polymorphism of isotactic polybutene-1 as revealed by microindentation hardness. Part II: correlations to microstructure

被引:92
作者
Azzurri, F
Flores, A
Alfonso, GC
Sics, I
Hsiao, BS
Calleja, FJB
机构
[1] CSIC, Inst Estructura Mat, E-28006 Madrid, Spain
[2] Dipartimento Chim & Chim Ind, I-16146 Genoa, Italy
[3] SUNY Stony Brook, Dept Chem, Stony Brook, NY 11974 USA
基金
美国国家科学基金会;
关键词
isotactic polybutene-1; polymorphism; microhardness;
D O I
10.1016/S0032-3861(02)00864-9
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
The influence of polymorphism on the micromechanical properties of isotactic polybutene-1 (iPBu-1) has been investigated by means of the microhardness technique. Hardness data, H, of form I (hexagonal) are shown to be notably larger than those of form II (tetragonal). The H values of both polymorphic forms are shown to depend on the molecular weight, M-w, and the crystallization temperature, T-c. The hardness behaviour with M-w and T-c has been correlated to the changes of degree of crystallinity and nanostructure as derived from small angle X-ray scattering. The hardness values for iPBu-1 infinitely thick crystals (Hc(c)(infinity)), of forms I and II, have been calculated for the first time. H-c(infinity) of form I is shown to be notably larger than that of form II. This result is a consequence of the denser packing of the hexagonal crystal modification, and accounts for the large difference in H values found for forms I and II. Finally, the variation of the mechanical b-parameter, proportional to the surface-free energy of the crystals, with molecular weight is discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:1641 / 1645
页数:5
相关论文
共 22 条
[1]   Microhardness under strain. 2. Microhardness behavior during stress-induced polymorphic transition in block copolymers of poly(butylene terephthalate) [J].
Apostolov, AA ;
Boneva, D ;
Calleja, FJB ;
Krumova, M ;
Fakirov, S .
JOURNAL OF MACROMOLECULAR SCIENCE-PHYSICS, 1998, B37 (04) :543-555
[2]   Polymorphism of isotactic poly(1-butene) as revealed by microindentation hardness. 1. Kinetics of the transformation [J].
Azzurri, F ;
Flores, A ;
Alfonso, GC ;
Calleja, FJB .
MACROMOLECULES, 2002, 35 (24) :9069-9073
[3]  
BAJPAI R, 1988, MAKROMOL CHEM, V20, P465
[4]   Crystal hardness and average distance between stable entanglements in melt crystallized polyethylene [J].
Bayer, RK ;
Calleja, FJB ;
Kilian, HG .
COLLOID AND POLYMER SCIENCE, 1997, 275 (05) :432-439
[5]  
Boneva D, 1998, J APPL POLYM SCI, V69, P2271, DOI 10.1002/(SICI)1097-4628(19980912)69:11<2271::AID-APP20>3.0.CO
[6]  
2-0
[7]  
Boor J., 1962, J POLYM SCI, V62, P70
[8]  
Calleja F.J.B., 2000, MICROHARDNESS POLYM
[9]  
Calleja F.J. Balta, 1994, TRENDS POLYM SCI, V2, P419
[10]  
CALLEJA FJB, 1990, MACROMOLECULES, V23, P5352