M. Azam Ali

In situ jute yarn composite with HEMA via UV radiation

Jute yarns soaked for 30 min in 2-hydroxyethylmethacrylate (HEMA) + MeOH solutions at different proportions [1–20% HEMA in MeOH (v/v)] were irradiated in situ with a UV lamp for different periods. The treated jute yarns that were washed in acetone after the irradiation to remove the unused excess monomer HEMA gained about 10% polymer loading with enhanced tensile strength (80%) and elongation (95%). The tenacity was not further increased by incorporation of a minute amount (1%) of novel additives into the HEMA + MeOH solutions, but elongation was enhanced up to 140% when the additive urethane acrylate (1%) was mixed with the solution.

New polyester acrylate resins from palm oil for wood coating application

The aim of this study is to investigate the potential use of palm oil and to prepare new UV (ultraviolet) radiation-curable acrylated polyester prepolymers, which could be used in the wood coating industry. Thus, palm oil-based acrylated polyester resins PEPP-1 (from refined, bleached, and deodorized palm oil) and PEPP-2 (from crude palm oil) were synthesized at the Advanced Oleochemical Technology Centre (AOTC) laboratory of Palm Oil Research Institute of Malaysia (PORIM). The performances of these resins with respect to their curing rate and physical-mechanical properties of cured products under UV radiation were studied. It can be concluded that newly synthesized UV radiation-curable polyester acrylated prepolymers (palm oil based), namely PEPP-1 and PEPP-2, can be used as radiation curable coating materials for wood coating applications.

Mechanical studies of methyl methacrylate treated jute and flax fibers under UV radiation

Jute and flax fibers were improved under UV radiation using methyl methacrylate (MMA) mixed with methanol (MeOH). There was a 30% enhancement of tenacity for these fibers against 3–8% grafting of MMA with the fibers. Incorporation of 1% of one of the additives 2-ethyl hexyl acrylate (EHA), urea (U), or N-vinylpyrrolidone to MMA + MeOH solution increased the grafting very slightly and enhanced the tenacity of jute by 110% and flax by 50%. Enhancement of elongation of the treated fibers was up to 30%.

Study on jute material with urethane acrylate by U.V. curing

Abstract Twenty different formulations were developed with urethane acrylate in the presence of different additives and co-additives. These formulations were applied to prepare different polymer films under u.v. radiation. Physical and mechanical properties of these cured films were studied. Jute material (hessian cloth) was coated with these formulations and cured under u.v. radiation. Different properties such as degree of polymer uptake, tensile properties, water absorption ability and degradability were studied. It was observed that the treated jute materials gained up to 97% polymer uptake, 115% tensile strength and 60% elongation over the untreated jute materials. The material behaved as a synthetic polymer with respect to durability in rain, water and soil. However, it was completely degraded by burying the materials in mud that contains 30% water.

Impregnation mode in wood plastic composite

Abstract Bulk monomer MMA was impregnated into simul, a fuel wood of Bangladesh, under vacuum and under normal temperature and pressure conditions in order to compare the mode of impregnation and its effect on various characteristic parameters of wood plastic composites. Methanol (MeOH) was used as the swelling solvent with methylmethacrylate (MMA) at MMA: MeOH = 70:30, v/v. Impregnation of the bulk monomer was very high under vacuum compared to that at normal condition; but the difference of grafting of MMA to the wood cellulose under these two impregnating conditions was much lower as compared to that of the uptakes of impregnating solution MMA + MeOH under these two modes of impregnation. Incorporation of additives to MMA + MeOH has substantially enhanced grafting, tensile strength, bending strength and compression strength of thcomposite of such an extent that there is virtually very little difference between vacuum impregnation and normal impregnation. Considering the available data it is suggested that the impregnation under normal condition is preferable beacuse different substrates of various sizes and shapes can be suitably impregnated under normal condition while vacuum impregnation has several limitations in this respect.

Comparative study of electron‐beam‐ and ultraviolet‐cured films of urethane acrylate

A urethane diacrylate oligomer was used to develop 40 different formulations in combination with eight different reactive diluents in the presence of five different coadditives. Thin films were prepared with these formulated solutions under ionizing radiation using either electron beam (EB) or ultraviolet (UV) rays. In the latter case, a photoinitiator was incorporated into the formulation. Physical, mechanical, and thermal properties of the cured films were studied. Tensile properties (strength and elongation) were almost double with the UV-cured films than those of the EB-cured films. Thermal behavior was also observed to be different in these two systems. These properties were correlated with the glass transition temperatures of the homopolymer of codiluents used.

Study of radiation-Cured thin films of aliphatic and aromatic urethane acrylate prepolymers

Eighty different formulations have been developed with aliphatic (M1200) and aromatic (M1100) urethane diacrylate oligomers in combination with eight functional monomer diluents and five comonomers. Thin polymer films were prepared with these formulations under electron beam (EB) and ultraviolet (UV) radiation. These films were then characterized. Glass transition temperatures (Tg) of the homopolymer of monomer diluents were correlated with physical properties of these films. Effects of modes of radiation, backbone structures of oligomers, and monomer functionalities on properties of the cured films are discussed.

Effect of Glass Transition Temperature (Tg ) in Thermal and Mechanical Properties of UV-Cured Films

Abstract Polymers of urethane diacrylate containing an aliphatic or aromatic backbone chain were prepared in the presence of a number of monofunctional and polyfunctional monomers under UV curing. These monomers have different glass transition temperatures ranging from — 110° to 250°C. Film hardness, gel content, tensile properties, and shape recovery characters of these polymers were determined. A correlation between the glass transition temperatures and these properties was established. The monomer N-vinyl pyrrolidone demonstrated the best performance in the preparation of polymers. Some of these polymer films have achieved a unique character of shape recovery phenomenon.

Relationship between physical-mechanical properties and glass transition temperatures of UV-cured polymers

Abstract A urethane acrylate oligomer (LR 8739) was used in combination with functional monomer diluents and codiluents possessing different glass transition temperatures (Tg s) to prepare thin polymer films under ultraviolet (UV) radiation. The amount of photoinitiator (Irgacure 184) and radiation dose intensity were optimized. The UV-cured films prepared at the optimized parameters were characterized to determine pendulum hardness, gel content, and tensile properties; these properties were correlated with glass transition temperatures of the UV-cured polymer films. The Tg values of the film were calculated on the basis of the Fox equation. The effect of codiluents on these properties was also investigated in consideration of the Tg values of the polymeric films prepared in the presence of codiluents.

Effect of diluents on thermal and mechanical properties of radiation cured films

Abstract About 30 formulations were developed out of 6 sets of reactive diluents with five co-diluents of different glass transition temperatures, ranging from −110 to 175°C. These formulations were used to prepare polymer films under ultra violet (UV) and electron beam (EB) radiations. Their mechanical and thermal properties such as tensile strength, elongation, deformation, folding character and shape recovery temperature were determined. Properties of UV cured films were compared with those of EB cured polymer of the same formulation. The UV cured films were found to possess better characteristics compared to EB cured films.