Preparation of Well-Compatibilized PP/PC Blends and Foams Thereof

Abstract

The performance of polypropylene-poly(ethylene brassylate) block and graft copolymers and a polypropylenepolycaprolactone graft copolymer as compatibilizers for polypropylene-rich polypropylene/bisphenol A polycarbonate (PP/PC, 80/ 20 wt/wt) blends was elucidated. The copolymers were synthesized either by metal-catalyzed ring-opening polymerization or transesterification of a presynthesized polyester, initiated by hydroxyl-functionalized PPs, which themselves were obtained by catalytic routes or reactive extrusion, respectively. Spectroscopic fingerprints of the copolymers from liquid-state nuclear magnetic resonance (NMR) in combination with scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), and rheology analyses of the blends indicated that the compatibilizers spontaneously organize at the interface of the two immiscible polymers leading to the formation of uniform, stable, nanophase morphologies. The effect of the compatibilizers on the performance of the PP/PC blends was evaluated, and wellcompatibilized PP/PC blends showed improved melt strength and strain hardening when compared to pure PP. This was verified by the successful foam extrusion using isobutane as a blowing agent of well-compatibilized PP/PC blends to low-density PP-based foams, for which normally long-chain branched PP is required.

Potential of Functionalized Polyolefins in a Sustainable Polymer Economy: Synthetic Strategies and Applications

“…The affinity of the iPP-g-PCL copolymers for the blend components was also evidenced by changes in their thermal and rheological properties. 3,47 The significant decrease in iPP melting points in the compatibilized iPP/PC blends by 5−7 °C and the increase in iPP crystallization temperature within 4−10 °C were attributed to the presence of the iPP-g-PCL copolymer, acting as a heterogeneous nucleating agent.…”

“…To prepare iPP-based nanoporous membranes, we started form randomly OH-functionalized iPP prepared as described above, which can easily be converted into their corresponding amphiphilic graft copolymers via transesterification of pre-synthesized polyesters or catalytic ring-opening polymerization (cROP) of lactones. , For this study, the graft copolymers were synthesized via cROP of ε-caprolactone and δ-valerolactone initiated by poly­(propylene- co -10-undecen-1-ol) with a propylene volume fraction of 30 to 50%. , This composition range was considered to be the most promising to achieve interconnected two-phase nanostructure morphologies, which are necessary for membrane preparation. As proven by atomic force microscopy (AFM) analysis, the iPP- g -PVL and iPP- g -PCL copolymers with a polypropylene volume fraction of 33–36% and equal to 46% afforded interconnected two-phase morphologies and the iPP- g -PVL, containing 39% iPP, exhibited a periodic lamellar structure (Figure a).…”

“…Polypropylene-polycaprolactone graft copolymers (iPP- g -PCL) were synthesized either by cROP or transesterification. ,,, The copolymerization reactions were initiated by either chain-end or randomly functionalized polypropylene, revealing M n ranging from 12 to 28 kg/mol and an OH content of 1 to 5 per polymer chain. As confirmed by scanning transmission electron microscopy (STEM) (Figure ), transmission electron microscopy (TEM) analysis (Figure ), and AFM analysis (Figure ), significant differences in PC droplet sizes and agglomeration predisposition were observed for the iPP-g-PCL compatibilized iPP/PC samples and the uncompatibilized reference.…”

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

“…So far, it's still a challenge to effectively prepare high-performance PC/PP alloys with approximate content. 12,13 In this work, a self-made compatibilizer was prepared by melt grafting reaction in the twin screw extruder, and three commercial compatibilizers were selected to systematically study effects of the compatibilizer type and content on the microstructure, mechanical properties, dielectric properties, and dynamic thermomechanical properties of PP/PC alloys.…”

“…Lireza Azizi et al 11 prepared PP/PC/SEBS alloys with different SEBS contents by the melt‐blending method, and it was found that the size and quantity of core‐shell particles of PP/PC/SEBS alloys increased with the increase of SEBS content. So far, it's still a challenge to effectively prepare high‐performance PC/PP alloys with approximate content 12,13 …”