Several coatings have been developed to reduce volatile organic component emissions, such as water-borne coatings, high-solid coatings, powder coatings, and radiation-curable coatings. Ultraviolet-curable coatings are one such boon to paint industries, not only reducing volatile organic components but also increasing productivity. Most polymers industrially produced nowadays are based on petroleum, which is a limited resource. Developing new procedures for making polymers based on natural renewable resources is a resounding theme for this decade and the future also. In response to both these needs, we have investigated the use of tobacco seed (Nicotiana rustica) oil in the synthesis of radiation-curable coatings. In this work, the alcoholysis of oil in various ratios with polyhydroxyl compounds was performed to prepare novel polyols, and these different polyols were reacted further with excess polyisocyanate to produce isocyanate-terminated prepolymers. The prepolymer were further reacted with hydroxyethyl methacrylate to produce urethane acrylate oligomers. The radiation-curable coating compositions were than prepared by the mixing of these oligomers with different reactive diluents, photoinitiators, and activators. These coating compositions were studied for their various physical and film characteristics, and certain coating compositions from tobacco seed oil were found to show very excellent overall coating properties.
Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent-based products and also because PUDs exhibit almost the same high performance levels as solvent-borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy-acrylic graft copolymer blocks. The epoxy-acrylic graft copolymers were first modified with ethylene diamine to give amine-terminated blocks which in turn reacted with isocyanate-terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain-extenders. The physico-chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy-acrylic copolymer blocks.
The resacetophenone‐formaldehyde (RAP‐F) resin showed to be a selective chelating ion‐exchange resin for certain metal ions. A batch equilibration method was used in the study of the selectivity of metal ion uptake. The method involved the measurement of distribution of a given metal ion between an aqueous solution and the resin. The study was carried out over a wide pH range and in media of various ionic strengths.
Three-component interpenetrating polymer network (IPN) matrix based glass fiber reinforced composites (GRC) have been prepared from the vinyl ester of an epoxy novolac resin (VEN), diglycidyl ether of bisphenol-A (DGEBA) (an epoxy resin), and methyl methacrylate (MMA) (a vinyl monomer). 2,2 -Azobisisobutyronitrile (AIBN) is employed as the initiator for both MMA and vinyl ester (VEN) resins, while DDM (diamino diphenyl methane) is employed for curing of DGEBA. All the IPNs and glass fiber reinforced composites based on these IPNs were characterized and are found to have good resistance to chemical reagents, good thermal stability, and good mechanical properties. C
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.
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