Toward Polyethylene–Polyester Block and Graft Copolymers with Tunable Polarity

Abstract

The synthesis and characterization of polyethylene−polyester block and graft copolymers and their potential as compatibilizers in polyethylene-based polymer blends are being described. The various routes to functionalized polyethylenes and the corresponding block/graft copolymers have been compared and evaluated for their scalability to industrial scale production. Hydroxyl chain-end and randomly OH-functionalized HDPE as well as randomly OH-functionalized LLDPE were employed as macroinitiators for producing the corresponding block and graft copolymers. These materials were prepared using two different strategies. The graf ting f rom approach entails catalytic ring-opening polymerization of lactones, i.e., ε-caprolactone and ω-pentadecalactone and hydroxyl-functionalized polyethylenes as macroinitiator. The alternative graf ting onto approach involves the preparation of block and graft copolymers via simple and convenient transesterification of polycaprolactone or polypentadecalactone with OH-functionalized polyethylenes. The copolymers were characterized in terms of their molecular weight (SEC), chemical structure (liquid state NMR), topology (MALDI-ToF-MS), supramolecular assembly (solid state NMR), and thermal properties (DSC analysis). The applied techniques for synthesizing the copolymers allow preparation of the products with sufficiently high molecular weight of the final materials. The copolymers were tested as compatibilizers for polyethylene/polycarbonate blends. As proven by SEM analysis, addition of the compatibilizers resulted in a significant improvement of the blend morphology.

Catalytic Hydroxylation of Polyethylenes

“… 60 , 63 Recently, hydroxylated HDPE obtained via ring-opening metathesis copolymerization of cyclooctene and 5-hydroxycyclooctene was used as macroinitiator for the grafting of PCL. 53 …”

Polystyrene Chain Growth Initiated from Dialkylzinc for Synthesis of Polyolefin-Polystyrene Block Copolymers

“…The further growth of polymer chains initiating from (polyolefinyl) 2 Zn may be useful for the syntheses of PO-based block copolymers [27]. Syntheses of polyethylene-block-polyester and polyethylene-block-polyether have been attempted with POs functionalized with -OH end groups, which were generated by treatment of the CCTP product (polyolefinyl) 2 Zn with O 2 [28][29][30][31]. We also discovered a method to grow polystyrene (PS) chains initiating from (polyolefinyl) 2 Zn that allows the syntheses of commercially more relevant PO-block-PS and PS-block-PO-block-PS in one-pot [32][33][34][35].…”

Polymers from macrolactones: From pheromones to functional materials

“…Catalysts based on Li, [6] Na, [6,87] K, [6,7] Mg, [88][89][90][91][92] Ca, [93,94] Al, [10,37,85,87,93,[95][96][97][98][99][100][101][102] Sn, [84,87,[103][104][105][106][107][108][109][110][111][112][113][114][115][116][117][118] Bi, [119][120][121][122][123][124] Zn, [4,5,…”

“…be employed as a strategy to prepare block copolymers and higher architectures of PMLs. For example, the eROP of MLs was initiated from a monohydroxylterminated polymer to prepare poly(butadiene)-b-PPDL,[164] methoxyPEG-b-PPDL,[137] methoxyPEG-b-poly(EB),[165] methoxyPEG-b-poly(DL)-b-PPDL,[166,167] and HDPE-b-PPDL [101]. Graft copolymers of poly(ethylene) (PE) and PPDL were similarly prepared by initiating the ROP of PDL from randomly hydroxylated HDPE or LDPE, or via transesterification of PPDL with randomly hydroxylated HDPE or LDPE [101].…”