Thermal Conductivity and Crystallography of Polypropylene/Polycarbonate/ Polypropylene-Graft-Maleic Anhydride Polymer Blend

Abstract

The effect of blending polycarbonate (PC) into polypropylene (PP) matrix polymer on thermal conductivity and crystal structure was studied. The blends consisted of 5% to 35% of PC with 5% compatibilizer (polypropylene-graft-maleic anhydride or PP-g-MA), were compounded using twin-screw extruder and shaped into standard tests samples by compression molding. The thermal conductivity values for PP/PC/PP-g-MA blends were ranging from 0.22 – 0.24 W/m.K. When compared to Hanshin – Shtrikman model, the highest difference in the thermal conductivity values was 28.2% shown in 90/5/5 composition. The deviation was due to the exclusion of factors such as PC particulates’ geometry, size, and dispersion in PP matrix. X-ray Diffraction (XRD) test revealed the blends’ structures comprised of medium-range order domains, referring to imperfect crystals with nanoparticles. The locations of peaks in the XRD spectrum also suggest that the pure PP’s monoclinic alpha crystal appeared in all PP/PC/PP-g-MA blends and there was no other crystal obtained in the blends. From the result, the discovered traits of crystal structure displayed influence on the thermal conductivity of the blends. At the same time, reactive compatibilization was suspected to take place at the interface of PP and PC phases when PP-g-MA was introduced.

Effect of compatibilizer on the structure and property of polycarbonate/polypropylene alloys

“…In the previous study, numerous modifications including reactive and additive compatibilization, have been introduced to further improve the properties of mobility, overcome its internal stress and also reduce the material cost. [3][4][5][6] It makes it possible for PC/PP alloy whose dielectric constant is relative low, applied in communication field. Compatibilizer plays an important role in preparing polymer alloy with high comprehensive performances, 7,8 and the technology of intruding the third phase to improve the compatibility of PC and PP has been widely studied.…”

“…Actually, no matter polyethylene (PE) or polypropylene (PP), as the two integral part of PO, the addition content can be added into PC is always small to achieve better performance in tensile strength and elongation at break. In the previous study, numerous modifications including reactive and additive compatibilization, have been introduced to further improve the properties of mobility, overcome its internal stress and also reduce the material cost 3–6 . It makes it possible for PC/PP alloy whose dielectric constant is relative low, applied in communication field.…”