Crystallization behavior of polybutene‐1 in the anisotropic system blended with polypropylene

Abstract

SynopsisDevelopment of supermolecular structure in drawn polypropylene (PP)/polybutene-1 (PB-1) blends was studied. PP (matrix)/PB-1 (70/30) blend films were drawn and heat-treated at fixed length or free ends at temperatures above the melting point of PB-1. It was found that a long axis of the PB-1 lamella is aligned perpendicular to the draw direction, and the c-axis of the PB-1 crystal is oriented perpendicular both to the draw direction and the plane of the surface of the blend film. Drawn, then heat-treated PP/PB-1 blend films gave a SAX pattern having a cross type scattering maximum on the meridian. It was confirmed that vertical scattering originates from the PB-1 crystal developed during melt recrystallization. It was p r o p o d that the structural development of PB-1 in drawn PP/PB-1 film can be explained on the basis of transcrystallization of PB-1 in the confined 2-dimensional space in the PP matrix. The kinetics of isothermal. crystallization of PB-1 was examined by use of a DSC technique. The result supports the conclusion that the heterogeneous nucleation of PB-1 followed by 2-dimensional crystal growth prevailed in oriented PP/PB-1 blend film.

Crystallization Behavior of Poly(ε‐caprolactone) Grafted onto Cellulose Alkyl Esters: Effects of Copolymer Composition and Intercomponent Miscibility

“…In many cases of bulk crystallization of polymers, when the nucleation takes place preferentially at the surface of a heterogeneous domain present in the molten system, the crystallization of the polymer component concerned would be usually accelerated, often attended by lowering of the growth dimension. [17,18] In the present case of the graft copolymers, however, the crystallization rate of the PCL component was generally suppressed, compared with that of ungrafted PCL; besides we observed a slower growth as ''spherulite'' of the crystal for any composition of the CA-and CB-series investigated, as the optical evidence is shown later. From these considerations and the finding of seriously reduced n values even for the CB-g-PCL samples composed of a miscible polymer pair, it seems natural to simply assume that the major factor responsible to the diminution of the kinetic parameter is the extremely slower diffusion of PCL chains due to the anchoring onto the semi-rigid cellulosic backbone.…”

Unique Orientation Textures Induced by Confined Crystal Growth of Poly(vinylidene fluoride) in Oriented Blends with Polyamide 6

“…A number of studies have been reported on the oriented crystallization of immiscible, but mechanically compatible, polymer blends consisting of two crystalline polymers, such as poly(propylene) (PP)/polyethylene (PE), [7][8][9] PP/ isotactic poly(butene-1), [10] PP/polyamide 11, [11] polyethylene glycol (PEG)/polyamide, [12] PCL/PE, [13] and poly(vinylidene fluoride)/polyamide 11. [14,15] If a component with a lower melting temperature is crystallized in the oriented matrix of another component with a higher melting temperature, some unusual orientation textures, such as orthogonal orientation, [8,10,11,14,15] or tilted orientation, [7][8][9]11] are induced in the dispersed phase.…”

“…[14,15] If a component with a lower melting temperature is crystallized in the oriented matrix of another component with a higher melting temperature, some unusual orientation textures, such as orthogonal orientation, [8,10,11,14,15] or tilted orientation, [7][8][9]11] are induced in the dispersed phase. The unique orientation behaviors have been explained either by epitaxial crystal growth on the polymer crystal, [11][12][13] thermal shrinkage stress, [7] or transcrystallization.…”

“…The unique orientation behaviors have been explained either by epitaxial crystal growth on the polymer crystal, [11][12][13] thermal shrinkage stress, [7] or transcrystallization. [10,14,15] The compatibility between two components in a blend should have important effects on the orientation behavior and the mechanical properties. From this point of view, the poly(vinylidene fluoride) (PVDF)/polyamide (PA) blend is an interesting system because of some specific interactions between the components.…”

“…Up to now, epitaxial crystallization, [11][12][13] thermal shrinkage stress, [7] and transcrystallization [10,14,15] have been used to interpret some new crystalline textures formed in some other blends. The possibility of an epitaxial crystallization of PVDF on the surface of PA6 is ruled out because there is no evidence of lattice matching between the PVDF and PA6 crystals.…”