Effect of chemical treatment on the tensile properties of short sisal fibre-reinforced polyethylene composites

Sisal fibers were subjected to various chemical and physical modifications such as mercerization, heating at 100 °C, permanganate treatment, benzoylation and silanization to improve the interfacial bonding with matrix. Composites were prepared by these fibers as reinforcement, using resin transfer molding (RTM). The mechanical properties such as tensile, flexural and impact strength were examined. Mercerized fiber-reinforced composites showed 36% of increase in tensile strength and 53% in Young’s modulus while the permanganate treated fiber-reinforced composites performed 25% increase in flexural strength. However, in the case of impact strength, the treatment has been found to cause a reduction. The water absorption study of these composites at different temperature revealed that it is less for the treated fiber-reinforced composites at all temperatures compared to the untreated one. SEM studies have been used to complement the results emanated from the evaluation of mechanical properties.

Effect of fiber surface modification on the mechanical and water absorption characteristics of sisal/polyester composites fabricated by resin transfer molding

Effect of wettability and ageing conditions on the physical and mechanical properties of uniaxially oriented jute-roving-reinforced polyester composites

Jute fiber is an important agricultural product. It is one of the most common natural fibers in Third World countries such as India, China, Bangladesh, etc. The jute industry has special importance in the economy of India and continues to be a major traditional earner of foreign exchange. However, it is facing tough competition from the synthetic fibers. Jute fibers find use in sophisticated fields like decorative and furnishing materials such as lamp shades, wall covers, curtains, upholsteries, etc. Today it is the least expensive fiber of mass consumption, at only a fraction of the cost of glass fibers; in terms of volume, jute is now the second most important fiber in the world, next to cotton. In the traditional applications in carpets, ropes, sacks, etc., jute fibers have been partially replaced by synthetic fibers which have some advantages compared to jute. In order to ensure a reasonable return to farmers, nontraditional outlets have to be explored for the fiber. One such avenue is in the...

Studies on Jute Composites—A Literature Review

Surface engineerings of polyacrylonitrile-based asymmetric membranes towards biomedical applications: An overview

A kinetic study of the graft copolymerization of methyl methacrylate onto jute fiber using KMnO4–malonic acid redox initiator system has been made. Effects of the concentrations of malonic acid, monomer, and KMnO4 on graft yield have been studied. Besides, the effects of temperature, acid, and reaction medium, some inorganic salts on graft yield have been investigated. The most remarkable features of the investigation include the proposition of a mechanism, derivation of rate expression for the grafting process, and characterization of the grafted fiber by thermogravimetric analysis.

A study on graft copolymerization of methyl methacrylate onto jute fiber

In recent years, the use of tetravalent cerium as an initiator of the graft polymerization of vinyl monomers on cellulosic and other textile materials has gained considerable importance because of its high grafting efficiency compared with the other known redox systems such as ferrous-hydrogen peroxide and thiosulphate-persulphate. There is a research program to investigate the vinyl graft polymerization onto various natural fibers using Ce(IV), permaganate, V(V), etc,. as catalyst and carbohydrates, i.e,. glucose, sucrose, etc., as cocatalyst with a view to achieving higher grafting efficiency. Use of sucrose, in particular, as the reducing component is of great industrial importance. This communication presents the results of studies of graft polymerization of methyl methacrylate onto silk fibers using Ce(IV)-sucrose redox system.

Graft polymerization of methyl methacrylate onto silk fibers with Ce(VI)–sucrose redox system

Aqueous polymerization of acrylonitrile initiated by the permanganate-glucose system has been studied under atmospheric conditions at 35 to 45°C. The rate of polymerization (Rp) is maximum at an optimum concentration of activator, but directly proportional to the concentration of monomer. Rp increases with an increase of metal ion concentration to a certain value and then decreases with a further increase of metal ion concentration. The effects of various water-soluble salts and solvents have been investigated. The end group of the polymer has been characterized by IR spectra. A suitable kinetic scheme has been proposed, appropriate rate expressions have been derived, and they are explained in the light of the experimental findings.

Studies on Vinyl Polymerization: Polymerization of Acrylonitrile by Permanganate-Glucose Initiator System

Studies have been made on the kinetics and mechanism of the retardation of v5+-cyclohexanone initiated polymerization of acrylonitrile by phenol in the temperature range 45–50°C. The effects of metal ion, monomer, phenol, HzSOI, some inorganic salts, and some organic solvents have also been studied. The unique observation in this investigation is the positive intercept obtained from the plot of [M]/Rp vs l/[M]. This type of observation is significantly different from previous studies on retarded polymerization. The values of composite rate constants k0kt/kikkpK were calculated from plots of [M]/Rp vs [M]−1. A suitable mechanism is put forth and the rate law based on the proposed mechanism is derived.

Retardation of V5+-Cyclohexanone Initiated Polymerization of Acrylonitrile by Phenol

The mechanism and kinetics of the retardation of the permanganate-initiated polymerization of acrylonitrile by phenol have been studied in the temperature range of 30 to 45°C. The effect of monomer, metal ion, phenol, sulfuric acid, organic solvents, and some inorganic salts on the polymerization has been studied. The most remarkable observation in the present investigation was the negative intercept obtained from a plot of [M]/Rp versus 1/[M] of the rate mechanism, This observation appears to be a general phenomenon for all inhibiting substrates. A reaction mechanism has been suggested and a suitable rate law has been proposed.

B. C. Singh

Papers

A study on graft copolymerization of methyl methacrylate onto jute fiber

Graft polymerization of methyl methacrylate onto silk fibers with Ce(VI)–sucrose redox system

Studies on Vinyl Polymerization: Polymerization of Acrylonitrile by Permanganate-Glucose Initiator System

Retardation of V5+-Cyclohexanone Initiated Polymerization of Acrylonitrile by Phenol

Retardation of Permanganate-Initiated Polymerization of Acrylonitrile by Phenol