No abstract

This research was conducted to investigate the linear expansion and resistance properties of a composite board (com-ply). This board was made of medium-density fiberboard (MDF) laminated using avocado (Persea americana), mahogany (Swietenia mahogani), and pine (Pinus merkusii) veneers. These three types of veneers were laminated on both surfaces of the MDF using adhesives, namely, epoxy and isocyanate. Glue (250 g･m −2 ) was spread on the surface, followed by cold press for 3 h with an applied pressure of 15 kg･cm −2 . The research result revealed that com-ply exhibited an increased dimensional stability compared with MDF, indicated by reduction in water absorption, thickness swelling, and linear expansion. The com-ply made of the pine veneer and isocyanate adhesive exhibited high density, water absorption, thickness swelling, and screw withdrawal load. The com-ply that exhibited the strongest resistance to drywood termite attacks was the one made of the mahogany veneer and isocyanate adhesive. Moreover, the com-ply that exhibited the biggest weight loss (3.6 %) was made of the pine veneer and epoxy adhesive. The results of this research may facilitate in manufacturing com-ply using the selected veneer and adhesive without the application of hot press.

Samama (Anthocephalus macrophyllus) is one of a pioneer indigenous fast growing species in Indonesia which have been used as traditional medicine for various diseases. The objectives were to determine the yield extract, to analyze their antidiabetic activity by inhibition assay for α-glucosidase enzyme activity and chemical analysis with GCMS. Extraction of leaves, bark and wood samples were done by using ethanol 95%. Fractionation the most active  ethanol extract was conducted by using n-hexane and ethyl acetate. The yield of ethanol extracts in leaves, bark and wood were 13.90%, 12.87%, and 2.18% respectively. Based on antidiabetic activity assay, the bark ethanol extract was the most active extract by the IC50 value of 5.86 μg mL-1. Phytochemical analysis on bark ethanol extracts showed that they contained flavonoid, quinon, triterpenoid, saponin and tannin which were assumed have high contribution in antidiabetic activities. The result of fractionation ethanol extract bark showed that the ethyl acetate fraction was the most active fraction (IC50 6.82 μg mL-1). GCMS analysis indicated the presence of dominant phenolic compounds such as pyrocatechol, antiarol, isopropyl myristate and phenol in which were suspected have antidiabetic activity. These results strongly suggested that ethyl acetate fraction of Samama bark was a potential natural source for antidiabetic agents.

Aesthetic and strength are not easy to be combined in one wood composite product. This research aimed at combining both utilizing MDF overlaid with avocado, mahogany and pine veneer. Seven types of MDF composite plywood (comply) were designed using two adhesive types of Epoxy and Isocyanat. The adhesive spread weight was 250 g m-2. Cold compression was conducted within 3 hours with the pressure of 15 kg cm-2. The research results showed that flexural modulus (MOE) and flexural strength (MOR) of PMI comply (pine veneer, isocyanat adhesive) increased respectively by 129.5% and 75.9% when compared to MDF. This research recommends that MDF comply may be utilized for the structural and non-structural purposes.