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Isotactic copolymerization of but-1-ene with polar vinyl monomers: the effect of ω-alken-1-ol comonomer content on phase behavior, melt rheology, mechanical and adhesive properties of functionalized poly(but-1-ene)s
Isotactic copolymerization of but-1-ene with bio-based undec-10-en-1-ol (M1), dec-9-en-1-ol (M2) and their silyl esters (M3–M5), catalyzed by C1-symmetric ansa-heterocene [Me2Si(η5-2,4,7-trimethelinden-1-yl)(η5-2,5-dimethyl-7H-cyclopenta[1,2-b:4,3-b']dithiophen-7-yl)]ZrCl2 (Zr1), activated by iBu3Al and MMAO-12, was explored for the first time. At [AlMMAO]/[Zr1] = 40 and [Monomer]/[Zr1] = 5,000, iBu2Al-protected ω-alken-1-ols have demonstrated highest activities and up to 16.7 mol% degrees of the comonomer incorporation with a formation of (co)polymers with moderate stereoregularity (for isotactic poly(but-1-ene) iPB Tm = 93.3 °C). At [AlMMAO]/[Zr1] = 400 and [Monomer]/[Zr1] = 100,000, iPB with Tm = 102.9 °C was formed; the presence of iBu2Al-protected undec-10-en-1-ol (M1-Al) led to substantial increase of the Mn of (co)polymers from 229 kDa (iPB) to 1193 kDa (copolymer containing 3.6 mol% of M1). XRD and DSC studies of the (co)polymers revealed a positive impact of the low comonomer content on the rate of Form II to Form I transition in iPB. Copolymers containing 0.3–0.6 mol% of OH groups showed improved melt rheology and mechanical properties, while the copolymer with 2.0 mol% M1 content turned out to be a hot-melt adhesive for steel with one and a half times higher bonding strength than commercial poly(ethylene-co-vinyl acetate).