Compatibility, adhesional interaction of components, impact strength, and rheological behavior of polycarbonate/polycarbonate-siloxane block copolymer

• Published in: Journal of applied polymer science Vol. 78; no. 4; pp. 858 - 869
• Main Authors: Pesetskii, S. S., Jurkowski, B., Koval, V. N.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 24.10.2000; Wiley
• Subjects: Applied sciences; block copolymer; Exact sciences and technology; impact strength; interphase adhesion; Organic polymers; Physicochemistry of polymers; polycarbonate; polycarbonate-poly(dimethyl siloxane); Properties and characterization; reactive processing; relaxation spectrometry; rheological behavior; scanning electron microscopy; Thermal and thermodynamic properties; thermal stability; Polymer blends; Mechanical properties; Experimental study; Adhesion; Heterogeneous mixture; Thermal stability; Interface properties; Impact strength; Phase separation; Carbonate copolymer; Kinetic parameter; Compatibility; Dimethylsiloxane copolymer; Polycarbonate; Block copolymer; Rheological properties
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/1097-4628(20001024)78:4<858::AID-APP200>3.0.CO;2-5

Polycarbonate (PC) blended with a polymer‐modifier polycarbonate–polydimethylsiloxane (PC–PDMS) of polyblock structure having equal molar ratios of soft (PDMS) and hard (PC) blocks have been investigated. The kinetics of adhesional interaction in blends and the analysis of interphase interaction conducted by using the relaxation spectrometry showed that intensive interactions between phases can occur. At a concentration of the modifier ≤5 wt %, these effects can lead to a partial compatibility of the components. The phase separation comes to completion when PC–PDMS content reaches 7 to 10 wt %. Here the impact strength of the blends improves compared with homopolycarbonate; this factor becomes less sensitive to the notch pattern or surface defects. The micro‐heterogeneous blends would fail by the multiple crazing mechanism. The mode of temperature vs impact strength relationship depends on the concentration of the modifier. Low shearing rates applied to the PC blends containing 3 to 7 wt % of PC–PDMS results in a lower melt flow index compared with that for a neat PC. The blends were more sensitive to shearing stresses than the homopolycarbonate. Therefore, they have lower viscosity at a high shearing rate than PC. Introduction of PC–PDMS into PC did not change its thermal stability significantly. The modifier inhibited the chemical crosslinking of PC chains if the melt had been kept for a long period. The optimal mechanical properties combined with improved processability were found in blends containing 7 to 10 wt % of PC–PDMS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 858–869, 2000