Synthesis and characterization of rigid polyurethane-palm oil based polyol/diaminopropane-montmorillonite nanocomposite foam

Issues on environmental impact and sustainability have driven the development of rigid polyurethane (PU)-palm oil based polyol (POP) /diaminopropane (DAP)-montmorillonite (MMT) nanocomposite foam. PU rigid foam derived from POP and polymeric 4,4-diphenylmethane diisocyanate (p-MDI), was successfully prepared via two steps-direct mixing method. Firstly, POP and DAP-MMT were mixed in a flask and stirred at 1500 rpm for 2 minutes to form a homogenous solution. Then, silicone surfactant and distilled water were added and further stirred for 2 minutes to form a pre-mixture. Later, p-MDI was added into the pre-mixture under high speed stirring at 1500 rpm for 45 seconds before charged into a mould. Fourier transform infrared energy peaks at 1533 cm-1, 1218 cm-1 and 1731 cm-1 of N-H, C-N and C=O groups confirmed the formation of urethane linkages. PU foam was prepared at 1:1 diisocyanate: polyol (NCO:OH) ratio exhibited a comparable compressive strength (4969 kPa) with the control PU (4999 kPa). Meanwhile the amount of silicone surfactant as a foam stabilizer at 2 part per hundred polyol (pphp) showed the highest compressive strength (8452 kPa) with uniform and finer cell size. The X-ray diffraction (XRD) test showed that samples with DAP-MMT contents at 2 wt % and 4 wt. % exhibited exfoliated structure while the scanning electron microscopy (SEM) micrographs showed the reduction of cell size of each sample. This morphology effect was clearly manifested on the sample with 4 wt. % MMT loading that had the highest compression strength and density which were 19648 kPa and 0.13 gcm-3. Results from water absorption test revealed that samples with 6 wt. % MMT loadings had about 31% reduction of water uptake against that of pure PU foam

Understanding intrinsic plasticizer in vegetable oil-based polyurethane elastomer as enhanced biomaterial

Renewable polyol is of increasing interest as a building block in biomedical elastomer for bearing biodegradable ester group and immaculate functionality. Derived from non-edible vegetable oil, a new class of elastomer was successfully functionalized with MDI and TDI. Crosslink densities were varied by regulating ratio of hydroxyl to diisocyanate (r) at 1/1.0, 1/1.1, and 1/1.2. Produced elastomers were examined by crosslink density, attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, tensile testing, and scanning electron microscopy. The obtained elastomers had subambient glass transition temperature (T g) suggested majority soft segment that acted as a continuous phase with intermediate phase separation. Medium conversion at gel point had enhanced physical properties. Highly elastic mechanical behavior was afforded from combination of side chains and high molecular weight polyol. At r = 1/1.2, MDI-based elastomer showed twofold improvement in Young modulus at slight expense of elongation. TDI-based elastomer accomplished elongation beyond 162%. Branching allophanate and biuret resisted early thermal breakdown by elevating activation energy. Frequency response and kinetic of thermal degradation provided beneficial perspective for elastomer characterization. The vegetable oil-based polyurethane was found able to resemble most of the physical properties of polycaprolactone (PCL)-derived polyurethane

Effects of silicone surfactant on the water absorption and surface morphology of rigid palm oil-based polyurethane foam

Polyurethane (PU) foams are widely used today in automotive and as insulation system. Due to environmental issues, efforts have been made to replace petrochemical polyol with natural-based polyol in PU foam production, without sacrificing any properties. This study aims to produce palm oil-based PU rigid foam for non-load bearing applications such as wall panel or insulation for buildings. Two parameters studied were percentage of water uptake and surface foam morphology. Palm oil-based polyol (POP) was reacted with polymeric 4,4-diphenylmethane diisocyanate (p-MDI) at 1:1 NCO:OH ratio. Water was used as blowing agent and silicone surfactant was added to produce stable rigid PU foam. The content of silicone surfactant was varied at 2 and 3 part by weight (pbw). The percentage of water uptake increased slightly with increasing surfactant contents due to siloxane portion of the surfactants, is thought able to reduce the surface tension of the cell, thus absorbing more water than 2 pbw surfactant content. The findings were supported with micrographs of scanning electron microscope (SEM) that showed a larger cell window area and thicker strut