The effect of crystallites on the rheological properties of microphase‐separated PVC‐PBA‐PVC triblock copolymers obtained by single electron transfer‐degenerative chain transfer living radical polymerization

Abstract

Linear and nonlinear rheological properties of poly(vinyl chloride) (PVC)-poly(n-butyl acrylate)-PVC triblocks of different compositions, obtained by single electron transfer-degenerative chain transfer living radical polymerization, are investigated, focusing on the effect of crystallites. Dynamic mechanical thermal analysis results show the existence of two glass transition temperatures, denoting microphase segregation. However, rather than phase separation, it is the presence of two types of crystals that melt at T m1 5 127 6 0.8 C and T m2 5 185 6 2 C, respectively, the factor that determines the rheological response of the copolymers. To the difference with PVC homopolymers, extrusion flow measurements at very low temperatures (T 5 100 C) are possible with the copolymers. A change in the viscositytemperature dependence is observed below and above the lowest melting temperature. Notwithstanding the microphase separation and the presence of crystallites, experiments carried out in conditions similar to industrial processing reveal a remarkable viscosity reduction for our copolymers with respect to PVC obtained by single electron transfer-degenerative chain transfer living radical polymerization, conventional PVC, and PVC/ [diethyl-(2-ethylhexyl)

Tuning the viscoelastic features required for 3D printing of PVC-acrylate copolymers obtained by single electron transfer-degenerative chain transfer living radical polymerization (SET-DTLRP)

“…Poly(vinyl chloride) (PVC) and poly(vinyl chlorideco-butyl acrylate) (PVC-BA) and poly(vinyl chloride-co-2-ethylhexyl acrylate) (PVC-EHA) copolymers were obtained by single electron transfer-degenerative chain transfer living radical polymerization (SET-DCTLRP) as described elsewhere [14,15]. Additionally, reference plasticized PVC-DOP samples were obtained by melt mixing of the previously used PVC with the appropriate amounts of bis (2-ethylhexyl)phthalate (DOP).…”

“…The composition of the copolymers was evaluated by proton nuclear magnetic resonance ( 1 H-NMR) spectra recorded in a Bruker Analytische Messetechnik 500, at 500.13 MHz of resonance frequency. The band assignment was conducted following the criteria of our previous works [14,15], and the lines between 4 and 5 ppm (corresponding to -CO-O-CH 2 -) were used to calculate the composition of copolymers. Additionally, the microstructures of different copolymers were confirmed by 13 C-NMR, as it is explained in reference [15].…”

“…In order to do so, we study the rheological features of different conventional and new PVC formulations, from rigid to flexible materials. Regarding the flexible materials, this study takes advantage of recently developed selfplasticised PVCs on the basis of random poly (vinyl chloride-co-butyl acrylate) and poly (vinyl chlorideco-2-ethylhexyl acrylate) copolymers obtained by single electron transfer-degenerative chain transfer living radical polymerization (SET-DTLRP) [14,15]. SET-DTLRTP technique is a valuable synthetic alternative for PVC derivatives as it permits to face problems derived from the synthesis of this polymer [16][17][18][19].…”

“…SET-DTLRTP technique is a valuable synthetic alternative for PVC derivatives as it permits to face problems derived from the synthesis of this polymer [16][17][18][19]. Additionally, the controlled character of this technology permits the synthesis of well-defined copolymers, from block to random structures, using diverse comonomers [14,15,20,21]. The selected materials offer the advantage of having low glass transition temperatures, as compared to PVC, which facilitates extrusion and adhesion between layers during additive manufacturing.…”

PVC/PBA random copolymers obtained by SET–DTLRP: Pressure effect on glass transition, rheology, and processing

“…This can cause a salubriousness problem, derived from the eventual migration of plasticizer, usually products related to phthalates family with different levels of toxicity . To face this challenge and reduce the T g of PVC, avoiding external plasticizers and procuring self‐plasticization, recently we showed that homogeneous random PVC–polybutyl acrylate (PBA) copolymers could be obtained by Single Electron Transfer–Degenerative Chain Transfer Living Radical Polymerization (SET–DTLRP) . This technique is a valuable synthetic alternative for PVC derivatives, as its controlled character permits the synthesis of well‐defined copolymers, from block to random structures, using diverse comonomers .…”