SISAL

About: SISAL is a research topic. Over the lifetime, 1878 publications have been published within this topic receiving 55528 citations.

Scanning electron microscopy study of raw and chemically modified sisal fibers

Abstract: Mercerization and acetylation treatments were applied to sisal fibers to enhance adhesion with polymer matrices in composites. The structures of the untreated and treated fibers were assessed with scanning electron microscopy. The waste from sisal-fiber decortication consisted of mechanical, ribbon, and xylem fibers, and their ultimate cells varied considerably in size and shape. After mercerization and acetylation, the fibers and conductive-vessel surfaces were successfully changed. The parenchyma cells were partially removed, and the fibrils started to split, because of the alkali action. This increased the effective surface area available for contact with the matrix. The mercerized and acetylated fibers were coated with cellulose acetate by the grafting of the acetyl group in the fibrils. The treatment used to remove lignin and hemicellulose caused changes in the fiber surface but did not damage the fiber structure because the fibrils remained joined in a bundle. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2333–2340, 2004

POSC—a partitioning and optimizing SISAL compiler

Abstract: Single-assignment languages like SISAL offer parallelism at all levels—among arbitrary operations, conditionals, loop iterations, and function calls All control and data dependencies are local, and can be easily determined from the program Various studies of SISAL programs have shown that they contain massive amounts of potential parallelism There are two major challenges in converting this potential parallelism into real speedup on multiprocessor systems First, it is important to carefully select the useful parallelism in a SISAL program, so as to obtain good speedup by trading off parallelism with overhead Second, it is important to do sequential optimizations, so that the sequential components (tasks) of the SISAL program have comparable execution times with sequential languages such as Fortran, Pascal and C The POSC compiler system described in this paper addresses both issues by integrating previous work on efficient sequential implementation of SISAL programs with previous work on selecting the useful parallelism in a SISAL program The combined approach is validated by real speedup measurements on a Sequent Balance multiprocessor

Properties of sisal fibre reinforced epoxy composite

Abstract: Sisal fibre reinforced epoxy composites have been prepared by hand lay-up technique followed by static compression, using various fibre weight fractions (15, 20, 25 and 30%). Mechanical properties, thermal properties, water absorption properties and dynamic mechanical analysis of sisal composites are investigated. The results show that the addition of sisal fibres in epoxy matrix up to 30 wt. % increases the mechanical, thermal and water absorption properties. The values of storage modulus and loss modulus increase with the increase in fibre content up to 25 wt. % and then decrease. The glass transition temperature ( T g ) is obtained from loss modulus and tan delta curve. The value of T g obtained from loss modulus curve is found to be lower than that obtained from tan delta curve.

Polyester moulding compounds of natural fibres and wollastonite

Abstract: Combination of natural fibres and wollastonite whiskers has been attempted as an alternative to glass fibre reinforcement in polyester dough moulding compounds. Natural fibres (sisal) and wollastonite were surface-modified with polyester compatible neo pentyl (diallyl) oxy, tri (dioctyl) pyro-phosphato titanate and gamma-methacryloxy propyl trimethoxy silane coupling agents, respectively. Reinforcing effect of wollastonite to a level of ∼50 wt% in an unsaturated polyester resin reveals a positive indication because of its favourable physico-mechanical properties and microstructural features. The optimization of short sisal and glass fibres in wollastonite/polyester system was carried out to formulate a doughy compound. It was found that ∼11 wt% sisal fibres in wollastonite/polyester and ∼3 to 5 wt% glass fibres in sisal/wollastonite/polyester give the optimum results. The high loss area observed at α and β transitions in dynamic mechanical analyser (DMA) traces supported the elastic behaviour of sisal/wollastonite/polyester moulding compared to corresponding wollastonite/polyester system. Based on these findings, a dough composition has been formulated and its suitability was assessed vis-a-vis to glass fibre–dough moulding compounds. It is observed that polyester dough moulding compound prepared from sisal/wollastonite reinforcement gives satisfactory results.

Evaluation of the mechanical properties of sisal–polyester composites as a function of the polyester matrix formulation

Abstract: In this work a comparative study on the impact and tensile properties of polyester/sisal fiber reinforced composites was undertaken. The polyester matrix was used bare and modified with: (1) a silane coupling agent; (2) a flame retardant system; and (3) a blend of the silane agent and the flame retardant system. The experimental results show that the flame retardant acts as a particulate reinforcement to the polyester matrix and the silane coupling agent acts as a plasticizer. The simultaneous addition of these two compounds to the polyester resin tended to decrease the performance of the composites. The results obtained show that strength or toughness could be tailored, and although none of the composites manufactured with the modified polyester matrices showed a significant improvement on the fiber–matrix interface strength, a better compromise between impact and tensile properties was obtained with the silane modified matrix. The critical fiber volume fraction was also evaluated and shown to be less than 10% for the sisal–polyester composite investigated here. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1209–1217, 2004