Development of a poly(methyl methacrylate‐co‐n‐butyl methacrylate) copolymer binder system

Abstract

SYNOPSISLow molecular weight poly (methylmethacrylate) and poly (methylmethacrylate-co-n-butylmethacrylate) emulsion-based polymers are developed for use as fugitive binders of high temperature powders to be used with the rapid prototyping method known as selective laser sintering. Kinetics of the homopolymerization of methylmethacrylate and n-butylmethacrylate are found to deviate from Smith-Ewart Type I1 predictions. Reactivity ratios for the monomer pair are determined and indicate the pair to yield random copolymers. Molecular weight was controlled by the addition of chain transfer agents. Several transfer agents were studied and one, Iso-octyl-3-mercaptopropionate, was selected for use with emulsion polymerizations. Glass transition temperatures of the homopolymers and copolymers were studied.

Kinetics of the seeded semicontinuous emulsion copolymerization of methyl methacrylate and butyl acrylate

“…The CTA accumulation may have occurred because of low reactivity 12 and masstransfer limitations. 15 The CTA used in this work, dodecanethiol, was rather reactive (k fCTA /k pMMA ϭ 0.112 16 ; k fCTA /k pAA ϭ 1.9 17 ), and the pre-emulsification seemed to overcome the low water solubility of the CTA. Reaction 4, carried out with 2 wt % CTA based on monomers, resulted in quite low molecular weights that could not be separated properly by the GPC columns; therefore, for this reaction only the final sample was analyzed by GPC.…”

Consolidation phenomena in laser and powder-bed based layered manufacturing

“…Indeed, these polymers are deliberately designed to depolymerise as an aid to their thermal removal in post-SLS processing. Polymers based on copolymers of n-butyl methacrylate (BMA) and methyl methacrylate (MMA) have been observed to also depolymerise during SLS processing [200,201]. The polymer binder may be added to the structural material in two ways: mixing [34,123] or coating [171,172,199,217].…”

Photocatalytic degradation of methyl methacrylate copolymers

“…In the past decade, although several workers have focused on the applications of poly(methyl methacrylate-co-butyl methacrylate) (MMA-BMA), poly(methyl methacrylate-co-ethyl acrylate) (MMA-EA) and poly(methyl methacrylate-co-methacrylic acid) (MMA-MAA) for water-based latex formulations [22], binders in selective laser sintering process [23], film formation for coatings and drug release [24], electrophoretic displays [25] and lithographic printing [26], studies on photo-stability were limited only to the respective homopolymers, viz. poly(alkyl)methacrylates [27], poly(alkyl)acrylates [28,29] and poly(methacrylic acid) [30].…”