SPHERULITES OF LONG-CHAIN BRANCHED CIS-1,4-POLYBUTADIENE

被引:19
作者
CHENG, TL [1 ]
SU, AC [1 ]
机构
[1] NATL SUN YAT SEN UNIV, INST MAT SCI & ENGN, KAOHSIUNG 80424, TAIWAN
关键词
D O I
10.1021/ma00078a008
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Morphological features of melt crystallized cis-1,4-polybutadiene (cPBD) were examined by means of polarized light microscopy. Three samples of similar molecular weight characteristics but different levels of long-chain branching were studied. The two low-branching samples exhibited typical spherulitic morphology. The spherulites were of banded texture at higher crystallization temperatures (T(c)); the band period decreased with decreasing T(c) and eventually became unidentifiable at T(c) < ca. -40-degrees-C. The spherulitic growth rate decreased significantly with the increasing level of branching. The effects of long-chain branching were most dramatically manifested by the surge of small (''dwarf'') spherulites in the highly branched cPBD; the dwarf spherulite stopped growing at a size of several microns and induced new dwarf spherulites among its periphery. The process repeated itself to the apparent end of crystallization. The melting temperature of slow-cooled or cold-crystallized samples decreased with the increasing level of branching. These observations were discussed in terms of the entanglement concept.
引用
收藏
页码:7161 / 7166
页数:6
相关论文
共 66 条
[1]   INFLUENCE OF MOLECULAR-WEIGHT ON THE MELTING AND PHASE-STRUCTURE OF RANDOM COPOLYMERS OF ETHYLENE [J].
ALAMO, RG ;
CHAN, EKM ;
MANDELKERN, L ;
VOIGTMARTIN, IG .
MACROMOLECULES, 1992, 25 (24) :6381-6394
[2]   CRYSTALLIZATION KINETICS OF RANDOM ETHYLENE COPOLYMERS [J].
ALAMO, RG ;
MANDELKERN, L .
MACROMOLECULES, 1991, 24 (24) :6480-6493
[3]  
[Anonymous], 1979, SCALING CONCEPTS POL
[4]   STRUCTURE OF POLYOLEFINS IN THE SOLID-STATE AS REVEALED BY SMALL-ANGLE NEUTRON-SCATTERING [J].
BALLARD, DGH ;
BURGESS, AN ;
CROWLEY, TL ;
LONGMAN, GW ;
SCHELTEN, J .
FARADAY DISCUSSIONS, 1979, 68 :279-287
[5]   THE CRYSTALLIZATION OF POLYETHYLENE .1. [J].
BANKS, W ;
GORDON, M ;
ROE, RJ ;
SHARPLES, A .
POLYMER, 1963, 4 (01) :61-74
[6]   LAMELLAR ORGANIZATION IN BANDED SPHERULITES OF POLYETHYLENE [J].
BASSETT, DC ;
HODGE, AM .
POLYMER, 1978, 19 (04) :469-472
[7]   ON CRYSTALLIZATION PHENOMENA IN PEEK [J].
BASSETT, DC ;
OLLEY, RH ;
ALRAHEIL, IAM .
POLYMER, 1988, 29 (10) :1745-1754
[8]   DISCUSSION OF SPHERULITIC CRYSTALLIZATION AND MORPHOLOGY - REPLY [J].
BASSETT, DC ;
VAUGHAN, AS .
POLYMER, 1986, 27 (09) :1472-1476
[9]   ON THE MORPHOLOGY OF MELT-CRYSTALLIZED POLYETHYLENE .3. SPHERULITIC ORGANIZATION [J].
BASSETT, DC ;
HODGE, AM .
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 1981, 377 (1768) :61-&
[10]   ON THE MORPHOLOGY OF MELT-CRYSTALLIZED POLYETHYLENE .1. LAMELLAR PROFILES [J].
BASSETT, DC ;
HODGE, AM .
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL AND PHYSICAL SCIENCES, 1981, 377 (1768) :25-+