Coir fibers. 3. Effect of resin treatment on properties of fibers and composites

Abstract

activation energy for viscous flow which in the present case can be calculated by the technique of Saini and Shenoy (1984) and is found to be equal to 8 kcal/mol.(4) The plots of 11 vs. .i. and Nl vs q2 under the required conditions can now be readily obtained by substituting the correct value of MFI in the unified curves or in eq 5 and 7.In the case of the solid-state deformation behavior, the necessary data can be regenerated from Figure 9 at any temperature of interest merely by determining the comparative stress value after 24 h of deformation. The value thus obtained as uo can be used in Figure 9 to generate the necessary expected long-term behavior of the PVDF product. The method of coalescence as demonstrated here should, in principle, be applicable to all creep experiments and help greatly in curtailing experimentation time. ConclusionThe present work demonstrates a very effective method for coalescing available data in the melt and solid state deformation behavior of PVDF. The resulting master curves are grade and temperature invarient in the case of the melt data and at least temperature invarient in the case of the solid-state data. The benefits of such master curves are that experimentation is simplified and the time required for experimentation curtailed. The unified curves, therefore, can act as hand tools for quick estimates of deformation behavior of PVDF necessary for design purposes.Nomenclature C, constant in eq 9 E activation energy for viscous flow, kcal (mol K) F force due to test load, dyne L test load, kg L , load at condition 1, kg L2 load at condition 2, kg LN nozzle length, cm m adjustable material parameter in eq 11, dimensionless n power law index in eq 13, dimensionless N model parameter in eq 7, dimensionless N , primar normal stress difference as defined in eq 10, Q flow rate, cm3/s R gas constant, kcal/mol RN nozzle radius, cm R, piston radius, cm t time scale, h T1 temperature at condition 1, K T2 temperature at condition 2, K Greek letters 4 shear rate, s-l p density, g/cm3 T~ zero shear viscosity, poise q apparent shear viscosity, poise X relaxation time, s go stress at the end of 24 h, d n/cm2 T shear stress, dyn/cm2 dyn/cm P g comparative stress, dyn/cm f primary normal stress difference coefficient, dyn d / c m z Registry No. PVDF, 24937-79-9. Literature Cited Carreau, P. J. Trans. SOC. Rheol. 1972, 16, 99. Gebauer, P. DynamA Nobel AG, 0-5210, Troisdorf, FRG, private communicaPugiia, L. Pennwait Corp., Philadelphia, PA 19102, private communication, Saini, D. R.; Shenoy, A. V. J . Mecromol. Sci., Phys. 1984, 822, 437. Shenoy, A. V.; Saini, D. R.; Nadkarni, V. M. J . Appl. Polym. Sci. 1982, 27, Shenoy, A. V.; Saini, D. R.; Nadkarni, V. M. Rheol. Acta 1883, 22, 209. Shenoy, A. V.; Saini, D. R. Rheol. Acta 1984a, 23, 368. Shenoy, A. V.; Saini, D. R. Chem. Eng. Commun. 1984b, 27, 1. Wagner, M. H. Rheol. Acta 1976, 15, 136. Wagner, M. H. Rheol. Acta 1977, 16, 43. tion, 1985.1985. 4399. This paper describes the treatment of bristle coir fibers with a dilute solution of unsaturate...

Scanning electron microscopy study of chemically modified coir fibers

“…These properties make the coir fiber extremely useful for various domestic and commercial applications. Another important application for coir, developed over the last few decades, is as part of the preparation of composites of different polymers, 2,3 In most of these applications coir fiber is used in both its natural and modified forms. A study on the surface morphology of a fiber that can be used in both its natural and chemically modified forms will be more helpful because user of the fiber will be applicable to several meaningful purposes.…”

FT-IR microscopic studies on coupling agents: treated natural fibres

“…In earlier studies,10, 14, 15 it was found that chemical interaction between surface modified natural fibre and resin matrix, as assessed by the fractographic events (fibre pull‐out) and tensile stress‐strain response of composites, had created doubts about the efficacy of treatments and necessitated further investigations into the chemical nature of the adsorbed species. Previous attempts on the use of Fourier transform infrared (FT‐IR) spectroscopy were limited only to identifying the presence of adsorbed species onto fibre surfaces,11, 16, 17 primarily because of the weak intensity of the vibrational spectra of adsorbed moieties whose concentration is very small as compared to the bulk reinforcement (fibre). This limited the scope of the approach especially when the interactions between the natural fibre surfaces and the coupling agents were to be investigated.…”

Effect of Fiber Length and Naoh Treatment on the Flexural Behavior of Coir Fiber Reinforced Epoxy Composite

“…A diameter of coir fiber was in the range of 0.2743mm. After that the coir fibers were immersed in the NaOH solution (2,4,6,8, & 10% concentration) for 10days. Thereafter, fibers were rinsed with water to remove the excess of NaOH sticking in the fiber.…”

“…However these traditional coir products consume only a small percentage of the potential total world production of coconut husk. Hence research and development efforts have been underway to find new use areas for coir including utilization of coir as reinforcement in polymer composite [6][7][8][9][10][11]. The alkali treatment of coir fiber for coir polyester composites.…”