Poly(acrylonitrile‐co‐methyl acrylate) copolymers: Correlation between copolymer composition, morphology and positron annihilation lifetime parameters

Abstract

A series of poly(acrylonitrile-co-methyl acrylate) copolymers of differing copolymer compositions are synthesized through free radical emulsion copolymerisation of methyl acrylate (MA) and acrylonitrile (AN) and by variation of the monomer feed ratios. The copolymers are characterized by NMR, SEC, WAXD, DMA, and positron annihilation lifetime spectroscopy. Results show that, there is a linear decrease in the glass transition temperature (T g ) of the copolymers and the MA content. There is also a progressive decrease in the crystallinity of the copolymers with increasing MA content. Positron results show a sigmoidal variation in the ortho positronium lifetime with an increasing MA content. The low MA content, semi-crystalline copolymers show a positive deviation from the linear additive relationship between the o-Ps lifetime and MA content, whereas the higher MA content amorphous copolymers show a negative deviation from the linear additive behavior. The o-PS intensity shows a linear behavior with MA content with a slight deviation from the additive linear behavior for the very high-content MA copolymer. These variations in the measured positron lifetime parameters are interpreted in terms of the copolymer morphology.

Low-temperature positron annihilation study of B+-ion implanted PMMA

“…One of the methods widely used to study structureproperties relationships in polymeric materials is positron annihilation lifetime spectroscopy (PALS) (see, for instance [11][12][13][14][15][16][17] and references therein). The various important information on the positronium (Ps) formation (the electronpositron bound state) [18,19] in polymers can be extracted from PALS analysis.…”

Reactive compatibilization of poly(methyl acrylate‐ran‐acrylonitrile)/poly(ethylene) blends through amine–anhydride coupling

“…MA was copolymerized with AN using AIBN as the initiator. Such copolymers were previously studied for carbon fiber applications . The goal for our synthesis was to make copolymers (and ideally terpolymers by inclusion of a monomer with a reactive functionality such as an amine) that had a sufficiently high AN composition to be useful as a barrier material (typically ∼40–50 mol % AN based on SAN copolymers for barrier against oxygen and carbon dioxide) and to use the binary system as the model non‐reactive polymer for blending studies with PE‐ g ‐MAn.…”

“…A Perkin–Elmer spectrum TWO with UATR accessory (also from Perkin‐Elmer) and diamond as the ATR crystal was used to qualitatively analyze MA/AN and MA/AN/PAS co/terpolymerizations. The peaks of interest for MA/AN copolymers were at ν = 1600–1800 cm −1 for the carbonyl stretch of MA and ν = 2200–2400 cm −1 for the nitrile stretch in AN . The peaks of interest for MA/AN/PAS terpolymers were at ν = 1600–1800 cm −1 for the carbonyl stretch of MA, ν = 2200–2400 cm −1 for the nitrile stretch for AN and ν = 3300–3500 cm −1 for the NH stretch of the primary amine of PAS …”

“…The peaks of interest for MA/AN/PAS terpolymers were at δ = 3.6 ppm for the methyl protons for MA, δ = 0.8–2 ppm for the backbone protons, and δ = 6.5–7 ppm for the styrenic protons of PAS. For all polymers, the AN content was calculated using the backbone protons, rather than solely the proton on the α‐carbon . CDCl 3 was used for H‐NMR analysis for the terpolymers, whereas deuterated DMSO‐ d 6 was used for the copolymers.…”

Effect of adding feldspar on free volume properties of crosslinked polyester studied by positron annihilation lifetime spectroscopy

“…3,7 During thermalization, the positron may annihilate with an electron from the material in free state or it may form, with the electron, a bound state called positronium (Ps) and then annihilation from the bound state takes place. Ps has two ground states called para-positronium (p-Ps), in which the positron and electron spins are antiparallel and decays with a lifetime of 125 ps, and the second form ortho-positronium (o-Ps), where the particles have parallel spins and have a mean lifetime of 142 ns in vacuum.…”