Jayant S. Parmar

Functional Poly(N-phenylmaleimide) as a Cation Exchanger—II

New cation exchangers based on the monomer, 4-(2,5-dioxopyrrolin-l-yl)benzoic acid (DPBA) were prepared, ie. poly(DPBA) and DPBA-divinylbenzene (DVB) copolymer. DPBA-styrene copolymer was prepared by addition polymeriation and DPBA-maleic anydride-styrene terpotymer by polycondensation of p-amino benzoic acid with poly (maleic anhydride-co-styrene). These polymers and copolymers were characterized by elemental analyses, number average molecular weight (M) IR spectral studies, viscosity measurements and thermogravimetry. The polymers exhibited polyelectrolytic behaviour in solution state and, in solid state, they possess good thermal stability. Preliminary results from ion exchange studies by the batch method indicate the possibility of the use of these polymers in the selective separation of several important metal ions.

Epoxy Based Thermal Stabilizer for Poly(Vinylchloride)

A tetrafunctional epoxy resin was prepared and characterized by epoxy equivalent weight, percentage nitrogen, IR spectroscopy and number average molecular weight (Mn) determined by GPC. The resin was evaluated as a thermal stabilizer for polyvinylchloride (PVC). The stabilizing efficiency was tested by yellowness index, HCl liberation, UV absorption, induction time, and changes in mechanical properties (tensile strength, elongation at break and Shore-A hardness). Epoxy resins with several epoxy groups are effective as in stabilizing PVC against dehydrochlorination during processing and use, compared with tribasic lead sulphate. The replacement of lead based stabilizers by epoxy stabilizers will remove the toxic effect of lead in water flowing through PVC pipes.

Polymerizable UV Stabilizers: I

The UV stabilizers 2-OH-4-allyloxybenzophenone and its oxime were prepared. They were copolymerized with styrene to give copolymers containing 2–8% UV stabilizers. The films were exposed to UV light and tested for any change in the carbonyl index, hydroxyl index, tensile strength, elongation at break and evaporation loss. The stabilization efficiency was evaluated by comparing with similar testing on pure polystyrene.

Chelating ion-exchange properties of homopolymer and copolymers of N-(4-carboxy-3-hydroxyphenyl))maleimide

Abstract The homopolymer of CHPM and its copolymers with styrene and divinylbenzene (DVB), prepared by addition polymerization, proved to be selective chelating ion-exchange polymers. The chelating ion-exchange properties of these polymers were studied for Ca2+, Cr3+, Fe3+, Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+ ions using a batch equilibrium method. The study was carried out over a wide pH range and in media of various ionic strengths. The polymers showed good selectivity for Fe3+, Ni2+ and Pb2+ ions compared to the other ions under study. The results of the separation study of Pb2+ from the Pb2+Ca2+ admixture and Fe3+ from the Fe3+Cr3+ admixture were promising. The regeneration study indicated that the polymers could be reused several times and the best stripping agent was 1.0 M H2SO4.

Stabilization of Polystyrene by Oligomeric UV Absorbers

Copolymers were prepared by the condensation reaction of formaldehyde and 2,4-dihydroxy benzophenone, 2-hydroxy-4-methoxy benzophenone and 2-hydroxy-4-butoxy benzophenone. The polystyrene films incorporated with these stabilizers were subjected to UV irradiation and then tested for any change in the carbonyl index, hydroxyl index, tensile strength, elongation at break and evaporation loss to evaluate the efficiency of the new stabilizers.