Graft Copolymerization of Styrene‐Maleic Anhydride Onto Poly(Vinyl Chloride) and Its Cross‐linking by Toluene Diisocyanate: Characterization, Thermal, and Mechanical Properties

Abstract

In this work, styrene‐maleic anhydride (St‐MA) copolymer was successfully grafted onto poly(vinyl chloride) (PVC) by means of chemical method in cyclohexanone medium. In this manner, the effects of various parameters such as total monomer content, monomers ratio, and initiator concentration on the grafting percentage (GP) and acid value (AV) were examined. The graft copolymers were characterized by Fourier‐transform infrared and nuclear magnetic resonance spectroscopy methods. Afterward, the cross‐linking reaction was carried out through MA hydrolysis and condensation reaction between maleic acid and produced diamines, by toluene diisocyanate (TDI) at the presence of hot water. The results showed that the GP and AV of PVC‐g‐(St‐MA) copolymers were considerably higher than those of PVC‐g‐MA and PVC‐g‐St with significant molecular weight. A gel content of 56% was attained with 1 phr TDI in PVC‐g‐(St‐MA) copolymer. The glass transition temperatures and mechanical properties of PVC‐g‐(St‐MA) samples were increased compared to pure PVC. Cross‐linked PVC‐g‐(St‐MA) showed improved mechanical properties than other samples, but the glass transition temperature of PVC backbone in this cross‐linked copolymer was disappeared due to its heavily dense structure. J. VINYL ADDIT. TECHNOL., 25:377–384, 2019. © 2019 Society of Plastics Engineers

Preparation of cross-linked PVC-g-(St-MA) copolymer/organoclay nanocomposites and investigation of chemical characteristics, morphology, thermal, and mechanical properties

“…Due to the low content of nanoclays in the samples, with incorporation of nanoclays into the pure cross-linked PVC- g -(St-MA) sample, no significant nanoclays absorption peaks were observed in the FTIR spectra. Along with the absorption bonds of pure PVC, 36,37 there are two new absorption bonds appearing at 1780 cm −1 and 2280 cm −1 region in all samples. The bonds at 1780 cm −1 and 1830 cm −1 are attributed to the stretching vibrations of the carbonyl functional groups of the MA, while the bond at about 2280 cm −1 is related to the stretching vibration of (–NCO) groups of TDI.…”

Self-Stabilized Precipitation Polymerization of Vinyl Chloride and Maleic Anhydride

“…Tuning the mass fraction of MAH units in the copolymer can endow PVM microspheres with desirable properties. However, a low content of MAH is required when it is used to modify the PVC resin by graft copolymerization (or direct copolymerization with VCM) via suspension or emulsion polymerization, mainly owing to the easy hydrolysis of the anhydride group in the aqueous phase. , Herein, we conducted the copolymerization of VCM with MAH under various monomer feed ratios, in which MAH content was controlled in the range of 10–40 wt % relative to the total monomer. All of the PVM microspheres (Figure a–d) displayed narrow PSD (1.03–1.08), and the D n increased gradually from 178 to 571 nm, with the MAH content increasing from 10 to 40%.…”

Physico-mechanical properties and cell microstructure of cross-linked PVC/organoclay nanocomposite foams prepared at various processing conditions

“…Additionally, the appearance of C=O and NH peaks at 1641 and 3636 cm −1 , respectively, indicates that isocyanate groups and maleic anhydride were cross-linked due to the presence of moisture, which produced amide linkages. 3,30,31 Therefore, during the molding step of pre-foam samples, in addition to the copolymer grafting reaction, cross-linking could be occurred in a small amount. With the increase of molding time, it is possible that two grafted copolymer chains on different PVC chains connect to each other and create a network.…”

“…1 Low price, high processability with additive materials, self-extinguishability, and great fire and chemical resistances are some of the excellent features of PVC which lead it to extensively be used in various fields, such as automobile, packing, and pipe preparation. 2,3 Among PVC-based productions, PVC foams, in addition to the aforementioned properties, possess high strength-to-weight ratios and low water absorption content. 4 PVC foams are widely employed as a core in sandwich-structured composites in different applications, including wind energy, aerospace, transportation and industrial applications, which require damage tolerance and weight loss.…”