Novel Polyolefins Containing Crystallizable Isotactic Polystyrene Side Chains

Abstract

Vinyl‐terminated isotactic polystyrene macromonomers were copolymerized with ethylene and 1‐octene to new polyolefin graft copolymers with crystallizable polystyrene side chains. The iPS content was varied from 4 to 78 wt.‐% using different metallocene and halfsandwich catalysts. No solubility problems of the stereoregular macromonomer occured, because iPS does not crystallize during polymerization. In addition the polymers show nanophase separation of the polyolefin backbone and the iPS side chains. The crystallization of iPS, having a melting point of about 200 °C, can be achieved by annealing. This synthesis strategy allows the fabrication of a new class of thermoplastic elastomers with improved heat distortion temperatures.magnified image

In situ compatibilisation of alkenyl-terminated polymer blends using cross metathesis

“…PP 8000 (6) was synthesized according to the procedure reported in the literature. 24 PCL 9000 (7) and PPDL 15000 (8). The vinyl end-capped poly(3-caprolactone) (PCL) and poly(pentadecalactone) (PPDL) were synthesized by the addition of 3 g of 3CL (26.5 mmol) or PDL (12.5 mmol), respectively, [Salen]AlEt (43 mg, 0.13 mmol), buten-1-ol (8.8 mg, 0.12 mmol) to toluene (3 g) in a 20 mL glass crimp cap vial under nitrogen, which was allowed to react overnight at 100 C, aer which full conversion (>95%) was conrmed by 1 H NMR analysis of the crude reaction mixture.…”

“…Polyolens containing unsaturated chain-ends are readily accessible since b-H or b-Me transfer to monomer is a common chain termination process for olen polymerisation catalysts. Typical examples are: polyethylenes (HDPE, LLDPE), 1,2 ethylene/ propylene copolymers (EP), 3 atactic polypropylene (aPP), 4 isotactic polypropylene (iPP), 4a,5 syndiotactic polypropylene (sPP), 6 but also isotactic polystyrene (iPS) 7 and others. Typically, the main use of these unsaturated macromolecules is as comonomers to be incorporated as medium and long chain branches by means of the "graing through" approach, affording so-called branch-block copolymers.…”

Isotactic poly(propylene‐co‐1‐pentene‐co‐1‐hexene) terpolymers: Synthesis, molecular characterization, and evidence of the trigonal polymorph

“…The use of metallocene catalysts from the late 1980s for the olefin polymerization introduced important changes as their single‐site characteristics leaded to produce polymers with nearly the same chain architecture, that is polyolefins with narrower molecular weight distributions rather than those synthesized using Ziegler–Natta catalysts and, consequently, with new properties. There are a variety of materials that, for the first time, could be prepared with high activity by these metallocene catalysts such as long‐chain‐branched polyethylene, polypropylenes with low amounts of oligomers and different tacticities (atactic, isotactic, isoblock, stereoblock, and syndiotactic), copolymers based on ethylene or propylene with a high proportion (5–30%) of long chain α‐olefins; elastomers made of ethylene, propene, and dienes (EPDM), syndiotactic polystyrene with a high melting point, homo‐ and copolymerization of cyclo‐olefins; and polymerization in the presence of fillers, filled polyolefins, or blends …”

Efficient Synthesis of Novel Polyethylene Graft Copolymers Containing Polyfluorosiloxane Side Chains

“…The first two methods are confronted with undesirable polymer degradation, occurrence of side reactions, or complicated synthetic routes. Thus, the macromonomer approach, i.e., the direct copolymerization of ethylene and macromonomer, has attracted widespread interest, because of the facile implementation and precise controllability over side-chain length and graft density. − …”