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Degree

Doctor of Philosophy, Case Western Reserve University, Macromolecular Science, 1991.

Abstract

This dissertation is concerned with the synthesis and characterization of several series of highly crystallizable homopolymers, block and random copolymers from 2-substituted 2-oxazolines. Phenyl (P) and Undecyl (U) oxazoline diblock (PU) and triblock (UPU) copolymers with almost the same P block length (about 10 monomer units) and various U block lengths (19-55 monomer units) were synthesized. They all have high water contact angles (geq107° for most of the block copolymers), low critical surface energies (21 dynes/cm), and low peel strength with pressure sensitive adhesives at room temperature for a short time after application. Their peel strength increases at elevated temperatures and/or long dwell times. Therefore two undecyl homopolymers with relatively high molecular weights (monomer/initiator ratio, M/I = 99 and 510) were made and tested as abhesives. It was found that unlike the phenyl/undecyl block copolymers, the undecyl homopolymers retain good adhesive properties up to 100°C. We attached a bulky, flexible siloxanyl group to the tail of the highly crystallizable alkyl side chain of decenyl oxazoline to see the effect of a bulky non-polar group on the polymer properties. 10-(pentamethyl disiloxanyl) decyl oxazoline (Si) was copolymerized with undecyl (U) or nonyl (N) oxazoline. Two series of random copolymers, U/Si and N/Si, were made with a total degree of polymerization of 100 and narrow molecular weight distributions. As we expected, their critical surface energies are almost the same as those of undecyl polymers, 21 dynes/cm, because their surfaces also consist of methyl groups. More interestingly, these two random copolymers crystallize two dimensionally over a broad composition range (10-65 mol.% of Si for N/Si copolymers, 10-50 mol.% of Si for U/Si copolymers). This proposed new crystalline structure was supported by both DSC (differential scanning calorimetry) and WAXD (wide angle x-ray diffraction) data.

Subject Headings

Chemistry, Polymer

Keywords

oxazoline homopolymers block copolymers

Advisor

Morton H. Litt

Pages

215p.

Document number: case1055356803
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=case1055356803

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