ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Recent studies of the morphology of semicrystalline polymers have demonstrated the inadequacy of the familiar fringed micelle concept. It is now generally recognized that polyolefins crystallize in a spherulitic form having a skeletal structure of coherent crystals with a fibrous habit. Crystallization occurs in two stages: (1) spherulitic growth of crystalline lamellae, and (2) partial crystallization of residual melt in regions between lamellae. The dependence of modulus on degree of crystallinity in polyethylene indicates that the crystalline network carries much of the elastic energy acquired when the plastic is subjected to stress. Two of the mechanical transitions are also related to morphological structure. The high temperature or α transition is attributed to motion within lamellae while the intermediate or β transition is attributed to motion in disordered regions between lamellae.
Zusätzliches Material:
12 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760050310
