SISAL

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

Nutrient depletion in Ferralsols under hybrid sisal cultivation in Tanzania

Abstract: . Sisal production in Tanzania has declined sharply in the past two decades because of a decrease in the area grown and a decrease in yields. As sisal is cultivated without manuring, depletion of soil fertility is considered one of the main causes of the declining yields. This paper presents a balance of the macronutrients N, P, K, Ca and Mg for sisal grown in a plantation in NE Tanzania on deep, red clay soils (Ferralsols). Annual fibre yields declined from 2.5 t/ha in the 1960s to about 1 t/ha in the 1980s. Hybrid sisal is a demanding crop and in ten years, with a total fibre yield of 11 t/ha, about 260 kg of N, 40 kg of P, 385 kg of K, 890 kg of Ca and 330 kg of Mg are removed in the harvested leaves. A comparison of soils after two and three 10-yr cycles of sisal production showed that in the third cycle the pH decreased by 0.5 units and that exchangeable bases were decreased by fifty per cent or more. The amounts of K, Ca and Mg removed from the soil were similar to those in leaves. However, soil analyses could not detect changes in total N and available P, possibly because of the large amount of total N in the soil and the lack of precision in the N and P analyses. In the Ferralsols, potassium is likely to become deficient first, followed by magnesium and calcium. The soil has little available P, and an increase in soil acidity may decrease it further and also create aluminium and manganese toxicities. In order to maintain sisal production, fertilization with P, K, Ca and Mg is necessary, and to improve yields N must also be applied.

Unconfined Compressive Strength of Bentonite-Lime-Phosphogypsum Mixture Reinforced with Sisal Fibers

Abstract: This paper presents the effect of sisal fibers on the unconfined compressive strength of bentonite The present study is aimed at determining the behavior of bentonite-lime-phosphogypsum reinforced with sisal fibers in a random manner The sisal fiber content was varied from 05 to 2 % The results indicated that the unconfined compressive strength of bentonite can be increased by the addition of lime, phosphogypsum and sisal fibers The increase in unconfined compressive strength was highest with 8 % lime, 8 % phosphogypsum and 1 % sisal fibers The reference mix reinforced with sisal fibers was able to bear higher strains at failure as compared to bentonite and bentonite- lime-phosphogypsum mixture With the increase in sisal fiber content (05 to 2 %) in reference mix, there was an increase in the unconfined compressive strength The bentonite lime-phosphogypsum-sisal fiber mixture will boost the construction of temporary roads on such problematic soils Further, its use will also provide environmental motivation for providing a means of consuming large quantities of phosphogypsum and natural fibers

Influence of glass and sisal fibers on the cure kinetics of unsaturated polyester resin

Abstract: The effect of grinded glass and sisal fibers (25 vol%) on the cure kinetics of composites of unsaturated polyester resin (UPR) was investigated by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The DSC analysis was carried out at four different heating rates (5, 10, 20 and 40 °C/min), and the cure enthalpy and activation energy (Ea) were determined according to the Flynn-Wall-Ozawa (FWO) method. The results showed that increasing heating rates promoted reduced reaction times. The sisal fiber-containing composites exhibit higher activation energy values for the cure process in comparison with the neat polyester resin and the glass fiber composites. This can be due to the presence of polar groups in the sisal components, which physically interact with the polyester resin and retard the cure reaction. Hence, as sisal fiber retarded the cure reaction of the UPR resin, it is suggested that the use of natural fibers in polymer matrix composites can affect the cure kinetics of the polyester resin.

Comparative Investigation on Mechanical Properties of Natural Fiber Reinforced Polyester Composites

Abstract: The aim of present experimental investigation is to compare the mechanical properties of Sisal, jute and kenaf fiber reinforced with glass fiber in polyester matrix hybrid composites. Hybrid composites were fabricated by hand lay-up technique. The tensile, flexural and impact tests were carried out on different composite samples as per the ASTM standards. It was observed that the tensile strength of jute/glass fiber composite is 1.94 and 1.59 times more than that of sisal/glass and kenaf/glass composites, respectively. The flexural load carrying capacity of sisal/glass composite is 3.4 and 2.83 times greater than those of jute/glass and kenaf/glass composites, respectively. Also, it can be seen that impact strength of jute/glass composite is almost equal to that of kenaf/glass composite and 1.13 times more than that of sisal/glass composite.

Effect of a Two Step Fiber Treatment on the Flexural Mechanical Properties of Sisal-polyester Composites

Abstract: Sisal fibers were chemically treated with a two-step treatment (first sodium sulfide aqueous solution and then acetic anhydride/acetic acid mixture) to promote better adhesion to a polyester resin matrix. The flexural behaviour of the composites was analyzed as a function of the time of immersion in distilled water, and there was an improvement for short times of immersion. The long term behaviour of the treated composites was, however, no better than that of the untreated ones. This could be because of the controlling role of plasticization of both the fibers and the resin matrix for the longer times of immersion.