A basic study of the kinematics, dynamics, and heat transfer occuring during tubular film extrusion of polyethylene is outlined. Three rheologically characterized polyethylenes, a lowdensity polyethylene (LDPE), a linear-low-density polyethylene (L-LDPE), and a high-density polyethylene (HDPE) were used in this study. The kinematics and stability of the tubular film process were investigated over a wide range of blow-up ratios, drawdown ratios, and frost-line heights. Local deformation rates along the bubble have been determined. Regions of stability and instability are described. Tensions and inflation pressures have been measured and expressed in terms of local elongational viscosities. Temperature profiles along the bubble were determined and interpreted in terms of local heat transfer coefficients. Positions of crystallization and temperature profiles have been noted and used to estimate rates of crystallization. The characteristics of the LDPE, LLDPE, and HDPE are contrasted.

This report describes the thermal decomposition behavior and the formation to investigate the flameretardant mechanism of organic metal salt in polycarbonate. Moreover, the flame retardancy of the polycarbonate with the addition of various kinds of organic metal salt was evaluated, and the difference in flame retardancy was considered. The decomposition of organic metal salt in polycarbonate during combustion promotes the decomposition of polycarbonate as a catalyst and the formation of a char layer on the surface that inhibits the supply of flammable gas and heat transfer. The flame retardancy is related to the final decomposition temperature of organic metal salt, and it is highest when it is close to the maximum decomposition temperature of polycarbonate.

Tiger stripe of injection molding of polypropylene (PP)/elastomer/talc blends was analyzed in terms of the morphology of the dispersed phase comprising elastomer components by using gloss and scanning electron microscopy (SEM). In addition, the contribution of the polymer design of PP, i.e., industrial block-type grade consisting of a homo-PP portion as the matrix and an ethylene propylene random copolymer portion as the domain is discussed. Local gloss measurement of the injected specimen along with the flow direction of the molten blends indicates a periodic fluctuation repeating higher and lower degrees of gloss, corresponding to the period of glossy and cloudy portions of the tiger stripe, respectively. These local gloss degrees are highly dependent on the morphologies of the dispersed phases near the surface layer of the injected specimen. The gloss increases when the ratio long axis (L) and diameter (D), L/D, of the dispersed phase are increased, and the gloss decreases when the L/D is decreased. Increasing the intrinsic viscosity of the ethylene-propylene rubber portion of the PP is an effective design factor for restricting the deformation against shear strain during injection process by giving the dispersed phases high elasticity.