Fabrication, structures and properties of Acrylonitrile/Vinyl acetate copolymers and copolymers containing microencapsulated phase change materials

Abstract

Acrylonitrile(AN)-Vinyl acetate (VAc) copolymers (AN/VAc) were synthesized by redox polymerization and microencapsulated phase change materials (MicroPCMs) were incorporated at the polymerization step. The effect of VAc monomers and/or the MicroPCMs on composition, melting point (T m ), exothermic peak value (T d ), average molecular weight (M η ), crystallinity of the copolymers were examined by Fourier Transform Infrared Spectroscopy (FTIR), Elementary Analysis, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TG), Ubbelohde viscosimeter and X-ray Diffraction (XRD). The compositions of the AN/VAc agreed well with the feed ratios. The melting peak shifted to a lower temperature (267 o C) with increasing concentration of VAc monomers and/or MicroPCMs, while the exothermic peak shifted to the higher temperature (324 o C). The average molecular weight of the copolymer was approximately 31,000. The crystallinity of the copolymers decreased with increasing content of VAc monomers and/or MicroPCMs.

A systematic review and meta‐analysis comparing complications following total joint arthroplasty for rheumatoid arthritis versus for osteoarthritis

“…PAN tends to decompose before its melting point reaches. It is well known that the melting and glass transition points of semicrystalline polymers can be reduced through incorporating comonomer units 15…”

Melt-Spinnable Polyacrylonitrile—An Alternative Carbon Fiber Precursor

“…To do this, it is necessary to disrupt the sequence of AN units to a sufficient extent so that a helical conformation of the chain is not formed. For example, AN and VAc copolymers (10–25 mol.%) with M η ~14–31 kg⋅mol −1 capable to melt were used to obtain microencapsulated phase change materials [ 67 ]. More attention is paid to MA, which has the similar ability to lower the melting point of PAN.…”

“…Comparative analysis of copolymers obtained by three synthesis routes-solution polymerization in DMF, precipitation, and suspension polymerizations in water showed that different compositions and MW of copolymers are required to form stable melts at 220 °C. The reason for this becomes clear if we take into account that the reactivity ratio of monomers varies for solution polymerization (r AN = 1.22–1.29, r MA = 0.61–0.96 [ 74 ]) and heterophase polymerization (r AN = 0.83, r MA = 1.17 [ 67 ]), as well as the dispersity of the resulting copolymers differs significantly. Unfortunately, the authors have varied all parameters simultaneously: copolymers composition, their compositional inhomogeneity, MW, and MWD.…”

Preparation and Stabilization of High Molecular Weight Poly (acrylonitrile-co-2-methylenesuccinamic acid) for Carbon Fiber Precursor

“…The average molecular weight of the viscosity of acrylonitrile was measured using the Ubbelohde viscometer method in a (50 ± 0.5) • C water bath. The calculation formula was as follows: [η] = 2.83 * 10 −4 M 0.759 ν : η represents the intrinsic viscosity calculated through linear extrapolation in Table S1 [19]. The copolymer compositions were measured using a Nicolet 8700 FTIR spectrophotometer at room temperature.…”

“…PAN has poor thermal conductivity, so a small amount of comonomer is usually added. Han et al copolymerized acrylonitrile with vinyl acetate to form a copolymer, and the comonomer could be used as a defect in the copolymer to improve thermodynamic performance, which is conducive to reducing the dipole-dipole interaction in the PAN system, reducing the stabilization temperature [19,36]. The DSC diagram of the PAN homopolymer, the P (AN-AA-MA) terpolymer, and the P (AN-co-MLA) copolymer were performed under a nitrogen atmosphere at a rate of 10 • C/min from room temperature to 350 • C in Figure 11.…”