The effects of melt grafted maleated polybutylene succinate on the properties of poly(hydroxybutyrate-co-hydroxyhexanoate)/polybutylene succinate blends

Poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHH)/poly(butylene succinate) (PBS) blends were prepared using a melt blending technique. A compatibilizer of maleated PBS (PBSgMA) was produced using reactive melt grafting by varying the maleic anhydride (MA) monomer concentration ranging from 3 to 10 parts per hundred resin (phr). Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the grafting reaction of the PBSgMA. The PBSgMA was incorporated in the 80PHBHH/20PBS and 50PHBHH/50PBS blends to investigate the effect of maleated compatibilizer on the tensile, flexural, drop weight impact, and water absorption properties of the blends with droplets dispersed and co-continuous morphology. The incorporation of PBSgMA increased the tensile and flexural strength of both the 80PHBHH/20PBS and 50PHBHH/50PBS blends, where the optimum properties achieved at 5 phr concentration of MA. The drop weight impact test results showed that uncompatibilized and compatibilized 50PHBHH/50PBS blends had higher critical strain energy release rate (G_c) than the neat PHBHH. However, blending and compatibilizing did not have a positive effect on the critical stress intensity factor (K_c) of the neat PHBHH. Scanning electron microscopy (SEM) confirmed the improvement of interfacial adhesion and PBS polymer dispersion in PHBHH/PBS blends when incorporated with 5PBSgMA. The water absorption test results demonstrated that compatibilized blends absorbed slightly more water than uncompatibilized blends due to the presence of hygroscopic carboxyl groups of the PBSgMA. However, water absorption effects were reversible and did not result in severe permanent damage to the blends.     

Current state of science and technology in the Muslim world

Reviews the current state of science and technology in the Muslim world in the light of the CASTASIA 1968 and the International Conference on Science in Islamic Polity 1983 recommendations of allocating 1.0 percent of GNP for R&D. The data presented indicates that the Muslim countries have not been able to achieve this target. OIC countries on the average spend 0.45 percent of their GNP on R&D as compared to 2.30 percent by OECD countries. Egypt which leads the Muslim countries spends 0.86 percent of its GNP on R&D as compared to 2.27 percent by Israel. Indonesia spends 0.17 percent as compared to 1.78 percent by Taiwan. Annual growth of R&D expenditure in a few Muslim countries, especially Turkey and Malaysia, is very encouraging. Muslims are also far behind in terms of R&D manpower. OIC countries have 8.5 scientists, engineers and technicians per 1,000 population as compared to 40.7 of world average and 139.3 for OECD countries. The contribution of Muslim countries to world science literature is also meagre. Forty-six Muslim countries contribute 1.17 percent to world science literature as compared to 1.66 percent by India and 1.48 percent by Spain. Twenty Arab countries contribute 0.55 percent as compared to 0.89 percent by Israel alone. Contribution to science literature is also analyzed on the basis of total population, literate population, and GNP per capita. Growth of science literature in many Muslim countries is faster than OECD countries.     

Analysis of vicilin (7S)‐class globulin in cocoa cotyledons from various genetic origins

Cocoa cotyledons contain vicilin (7S)‐class globulin (VCG), a major storage protein. It is the native source of oligopeptides and free amino acids which have been identified as precursors of cocoa‐specific aroma and are formed through proteolysis during fermentation. High‐resolution electrophoresis of native proteins isolated from ripe, unfermented cocoa cotyledons harvested from different cultivars was used to determine genetic differences of the genotypes. Flavour differences have been reported to exist after standard fermentation in cocoa beans harvested from various genotypes. In this paper, SDS‐PAGE and 2D IEF/SDS‐PAGE polypeptide separation patterns are shown which were separately isolated from cotyledons of various genetic origins. Cotyledons from three cultivars belonging to genetically distant varieties and a hybrid, Criollo, Forastero and Trinitario, did not reveal any analytical identity differences of VCG subunit polypeptide bands. Additionally, proteins of cotyledons harvested from three of those clones which were reported to produce genotype‐specific flavour differences in raw cocoa after standard fermentation, SCA 12, UIT1 and PBC 140, when analysed in the same way, did not indicate differences. Thus the cotyledon storage proteins from various genetically different cocoa trees are, within methodological limits, the same. We conclude that aroma differences in raw cocoa harvested from various genotypes are the result of other genetic, physiological or curing‐related factors, but are not due to genetic differences of aroma precursors derived from storage proteins. © 2002 Society of Chemical Industry     

Density and humidity gradients in veneers of oil palm stems

Large variations in the stem of oil palm in terms of moisture content and density hinder its full utilization in the plywood industry. In this study, the density and moisture content (MC) pattern throughout the trunk of the oil palm tree were measured and established. The veneer samples were taken from various sections i.e., top, bottom, outer and inner parts of the trunk and the density and moisture content of each veneer were then measured. The results showed that there was a decrease of density and an increase of moisture content in the veneers as they were peeled progressively towards the inner portion of the trunk. It was also discovered that veneers taken from the top part of the stem had higher density but did not have a significant difference in MC compared to veneers taken from the bottom part of the stem.     

Simulation of dynamic response for steel fibrous concrete members using new material modeling

Present investigation includes formulation of new nonlinear material constitutive mathematical models of steel fiber reinforced concrete (SFRC) material depending on many experimental data available in literature. Eight-node degenerated plate elements were used to investigate the dynamic performance of SFRC slabs and beams under blast and impact loadings. Two models are used to simulate the compressive behavior of fibrous concrete material namely the elastic perfectly plastic and strain hardening plasticity models. Dynamic yield function is assumed to be a function of strain rate. Geometrical nonlinearity in the layered approach is considered in the mathematical model, which is based on the total Lagrange approach taking into account Von Karman assumptions. Implicit Newmark with corrector–predictor algorithm was adopted for time integration solution of the equation of the motion. Concrete crack pattern has been determined according to smeared fixed crack approach. Present numerical outputs show suitable agreement with experimental results available in literature which include deflections and failure pattern.     

Novel Antifungal Peptides Produced by Leuconostoc mesenteroides DU15 Effectively Inhibit Growth of Aspergillus niger

The ability of Leuconostoc mesenteroides DU15 to produce antifungal peptides that inhibit growth of Aspergillus niger was evaluated under optimum growth conditions of 30 °C for 48 h. The cell‐free supernatant showed inhibitory activity against A. niger. Five novel peptides were isolated with the sequences GPFPL, YVPLF, LLHGVPLP, GPFPLEMTLGPT, and TVYPFPGPL as identified by de novo sequencing using PEAKS 6 software. Peptide LLHGVPLP was the only positively charged (cationic peptides) and peptide GPFPLEMTLGPT negatively charged (anionic), whereas the rest are neutral. The identified peptides had high hydrophobicity ratio and low molecular weights with amino acids sequences ranging from 5 to 12 residues. The mode of action of these peptides is observed under the scanning electron microscope and is due to cell lysis of fungi. This work reveals the potential of peptides from L. mesenteroides DU15 as natural antifungal preservatives in inhibiting the growth of A. niger that is implicated to the spoilage during storage.     

Changes in polyphenol ability to produce astringency during roasting of cocoa liquor

Polyphenols in cocoa products determine the astringent sensation due to their interaction with salivary proline‐rich protein. Changes in the ability of polyphenols to produce astringency during cocoa roasting have been studied through an evaluation of the polyphenol–protein interaction in cocoa cake/liquor roasted at 120 °C for 45 min, with and without enrichment with polyphenol extract. Roasting decreased the capacity of polyphenols to interact with protein, causing a decrease in astringency. However, the polyphenol–protein interaction products after roasting could still be oxidized enzymatically and most probably would still give cocoa products beneficial effects as functional food. Copyright © 2005 Society of Chemical Industry     

Effects of jackfruit waste flour on the properties of poly(vinyl alcohol) film

A series of biodegradable polymer films based on poly(vinyl alcohol) (PVOH) and jackfruit waste flour (JWF) was prepared in the presence of water and glycerol and cast by a solution casting method. The JWF was introduced as a promoter of biodegradability. The blended films were evaluated for their tensile properties, water absorption, water vapor transmission rate (WVTR), and degradation behavior under different environmental conditions such as natural weathering and natural soil. The tensile strength (1.7–6.4 MPa) and elongation at break (13–108%) of the PVOH/JWF films were lower than those of unfilled PVOH film (26MPa and 238%). However, the Young's modulus values (157–196 MPa) of the PVOH/JWF films were higher than that of unfilled PVOH film (137 MPa). The PVOH/JWF blended films showed higher water absorption and WVTR, which increased with increasing JWF content. Biodegradability tests revealed that the presence of JWF stimulated the degradation rate and caused the weight loss and reduction in tensile properties of the PVOH/JWF blended films. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Kenaf fiber reinforced composites: A review

The development of high-performance engineering products made from natural resources is increasing worldwide, due to renewable and environmental issues. Among the many different types of natural resources, kenaf plants have been extensively exploited over the past few years. Therefore, this paper presents an overview of the developments made in the area of kenaf fiber reinforced composites, in terms of their market, manufacturing methods, and overall properties. Several critical issues and suggestions for future work are discussed, which underscore the roles of material scientists and manufacturing engineers, for the bright future of this new “green” material through value addition to enhance its use.