Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and released the least toxic hydrogen cyanide (HCN) gas under thermal degradation. The normalized compressive strength of the EFBPUF at the NCO index of 120 is also comparable with the strength of the PUF produced using petrochemical polyol.
In Malaysia, core oil palm trunk (COPT) is one of the biomass that has been left underutilised due to its low properties. Nonetheless, metabolites contained in COPT sap may provide an alternative natural resources for bio-chemicals and pharmaceuticals. Metabolites such as sugars are easily affected by analytical factors during storage. In this study, the changes of metabolite contents in COPT sap stored at different storage durations, conditions and temperatures were observed by using gas chromatography-mass spectrometry (GC-MS) based metabolomics approach. The changes of metabolite contents, particularly sugars and organic acids were analysed using univariate and multivariate statistical analysis. The separation trends observed in the principal component analysis (PCA) score plot was greatly influenced by storage temperatures. However, two-way analysis of variance (ANOVA) revealed that the majority of significant metabolites (P<0.05) was strongly influenced by storage durations. The metabolite increased significantly when COPT was stored as raw rather than sap. The highest sugar concentrations in COPT were found at 10°C for one month (R-10-1M). Furthermore, the organic acids increased significantly when stored at 4°C for one month (R-4-1M). The results indicated different storage durations, conditions and temperatures led to variation in the COPT sap metabolite content.
Selulosa ialah polimer semula jadi yang boleh diperbaharui dan biasanya ditemui di dalam dinding sel tumbuhan. Interaksi hidrofobik yang kompleks serta sifat amfifilik menyebabkan ia sukar dilarutkan dan seterusnya membataskan penggunaannya secara menyeluruh. Pemahaman kepada struktur kimia dan fiziknya membolehkan proses pelarutan berlaku dengan penggunaan jenis pelarut yang bersesuaian. Namun, pelarut sedia ada bukanlah yang terbaik dan efisien terhadap pelarutan selulosa. Sehingga kini, kajian kepada jenis pelarut dan mekanisme pelarutan masih menjadi topik utama penyelidikan. Selulosa yang terlarut pula boleh dijana semula kepada produk fizikal yang lain, contohnya hidrogel, aerogel, kriogel dan xerogel. Produk yang dijana semula daripada selulosa yang terlarut boleh diacukan kepada pelbagai bentuk yang mempunyai struktur tulang yang kuat dan bersifat hidrofilik, bioserasi dan terbiodegradasi. Potensi dalam aplikasi yang pelbagai serta terbukti sebagai alternatif kepada polimer sintetik menjadikan polimer semula jadi ini berpotensi besar dalam bidang sains dan teknologi. Maka, ulasan kajian terhadap selulosa, jenis pelarut serta produk yang dijana semula daripadanya menjadi fokus dalam penulisan makalah ini.
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