## ABSTRACT

Keywords ..................................................................................................293 References .................................................................................................293

A polymers orientation by uniaxial tension can be accompanied by essential volume changes. These changes are realized by different mechanisms, defined by polymeric material structure. So, at uniaxial drawing of semicrystalline high density polyethylene (HDPE) volume change up to 30% was observed, which is due to cracks formation, oriented perpendicularly to tension direction [1]. At solid-phase extrusion of polymerization-filled compositions (componors) on the basis of ultra-high-molecular polyethylene (UHMPE) volume increase is due to interfacial boundaries polymer matrix-filler breakdown and it can be reached of ~10% [2]. However, in the case of melt uniaxial tension volume changes are nit observed. It has been assumed [1] that in this case at melt orientation macromolecules high mobility and structure ordered elements absence are ensured viscous medium tension without microvoids formation and such oriented melt crystallization results to formation of the system, not consisting of pores and other continuum interruptions.