Syntheses of graft and star copolymers possessing polyolefin branches by using polyolefin macromonomer

Abstract

Graft and star copolymers having poly(methacrylate) backbone and ethylene-propylene random copolymer (EPR) branches were successfully synthesized by radical copolymerization of an EPR macromonomer with methyl methacrylate (MMA). EPR macromonomers were prepared by sequential functionalization of vinylidene chain-end group in EPR via hydroalumination, oxidation, and esterification reactions. Their copolymerizations with MMA were carried out with monofunctional and tetrafunctional initiators by atom transfer radical polymerization (ATRP). Gel-permeation chromatography and NMR analyses confirmed that poly(methyl methacrylate) (PMMA)-g-EPR graft copolymers and four-arm (PMMA-g-EPR) star copolymers could be synthesized by controlling EPR contents in a range of 8.6-38.1 wt % and EPR branch numbers in a range of 1-14 branches. Transmission electron microscopy of these copolymers demonstrated well-dispersed morphologies between PMMA and EPR, which could be controlled by the dispersion of both segments in the range between 10 nm and less than 1 nm. Moreover, the differentiated thermal properties of these copolymers were demonstrated by differential scanning calorimetry analysis. On the other hand, the copolymerization of EPR macromonomer with MMA by conventional free radical polymerization with 2,2 0 -azobis(isobutyronitrile) also gave PMMA-g-EPR graft copolymers. However, their morphology and thermal property remarkably differed from those of the graft copolymers obtained by ATRP. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: [5103][5104][5105][5106][5107][5108][5109][5110][5111][5112][5113][5114][5115][5116][5117][5118] 2005

End-functional polyolefins for block copolymer synthesis

“…See also related work utilising alumination. [50][51][52] Also noteworthy are macromonomers based on PE bearing methacrylic end groups, achieved by Matyjaszewski and coworkers utilising Pd(II) α-diimine catalysts (Figure 8). 53 The functional PE was then able to copolymerise with n-BA under ATRP conditions.…”

“…11,71 and generally involves in situ chain transfer to e.g. organoboranes, 35,36,72,73 alkyl aluminiums 51,[74][75][76][77][78] and alkyl zincs 49,[79][80][81][82] during catalytic olefin polymerisation, followed by oxidation. Chung and coworkers reported the synthesis pf PE-b-PEO by anionic ROP of ethylene oxide following oxidation and metalation of boranefunctionalised PE.…”

Solid and thermal properties of ABA‐type triblock copolymers designed using difunctional fluorine‐containing polyimide macroinitiators with methyl methacrylate

“…Typical monomers include styrene, (meth)acrylates, (meth)acrylamides and acrylonitrile, which contain substituents that can stabilize the propagating radicals 8. The ATRP technique is useful for obtaining well‐defined polymers with various architectures such as block and graft polymers,9–19 as well as allowing control of both the molecular weight and the molecular weight distribution of polymers. Blázquez et al reported the preparation of aromatic amine‐terminated PMMA using the ATRP method.…”

Re: Jolly N, Garg RK, et al. Amplatzer® septal occluder device for closure of aortic pseudoaneurysms. Catheter Cardiovasc Interv 2007; 70:619–620. DOI: 10.1002/ccd.21188.

“…Controlled polymerization techniques have been adopted to prepare well‐defined polymers with controlled molecular weight, polydispersities, and terminal functionalities 11–23. Of particular interest today is a combination of two of these processes for the formation of new polymeric materials 18, 19, 21, 24–30. The combination of ring‐opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP) was employed to prepare some materials 12, 14.…”