Fu-Hung Hsieh

Water‐blown flexible polyurethane foam extended with biomass materials

Soy protein isolate, soy fiber, and cornstarch (0–40% polyether polyol) were incorporated into a flexible polyurethane foam formulation. Stress–strain curves of the control foam and foams containing 10–20% biomass material exhibit a considerable plateau stress region but not for foams extended with 30–40% biomass materials. An increase in biomass material percentage increases foam density. An increase in initial water content decreases foam density. Foams extended with 30% soy protein isolate, as well as foams extended with 30% soy fiber, have notably greater resilience values than all other extended foams. The comfort factor increases with increasing percentage of biomass material in foam formulation. Foams containing 10–40% biomass materials display significantly lower values in compression-set than the control foam.

Comparative study of physical properties of water-blown rigid polyurethane foams extended with commercial soy flours

The use of renewable resources (mainly carbohydrates) in rigid polyurethane foam has been known to offer several advantages, such as increased strength, improved flame resistance, and enhanced biodegradability. Less attention has been directed to inexpensive protein-based materials, such as defatted soy flour. The objectives of this study were to develop water-blown rigid polyurethane foams, containing defatted soy flour, that have acceptable or improved physical properties which also lower the cost of the foam formulation and to compare the properties of developed foams extended with three kinds of commercial soy flour. Water-blown low-density rigid polyurethane foams were prepared with poly(ether polyol)s, polymeric isocyanates, defatted soy flour, water, a catalyst mixture, and a surfactant. Soy flour and the initial water content were varied from 0 to 40% and from 4.5 to 5.5% of the poly(ether polyol) content, respectively. A standard laboratory mixing procedure was followed for making foams using a high-speed industrial mixer. After mixing, the mixture was poured into boxes and allowed to rise at ambient conditions. Foams were removed from boxes after 1 h and cured at room temperature for 24 h before measurement of the thermal conductivity and for 1 week before other property tests. Foam properties were determined according to ASTM procedures. Measurement of the physical properties (compressive strength, modulus, thermal conductivity, and dimensional stability under thermal and humid aging) of these foams showed that the addition of 10-20% of three kinds of soy flour imparted water-blown rigid polyurethane foams with similar or improved strength, modulus, insulation, and dimensional stability.

Properties of Biobased Rigid Polyurethane Foams Reinforced with Fillers: Microspheres and Nanoclay

The effect of incorporating 1–7% microsphere and nanoclay fillers on the physical properties of polyurethane (PU) foams containing 15% soybean oil-based polyol was investigated. Increasing filler percentage reduced the PU foam density. The compressive strength of PU foams decreased slightly when increasing the microsphere content from 1 to 3% and then increased. At 7% microsphere content, the foams displayed the same compressive strength as the control foams made from 100% petroleum polyol. For PU foams reinforced with nanoclay, their compressive strength changed little from 1 to 5%, but decreased at 7% due to a lower density and weaker matrix structure. Foams containing 5 to 7% microspheres or 3 to 7% nanoclay had density-compressive strength comparable or superior to the control. Foams reinforced with fillers had more cells and smaller cell size than foams made from 15% soy-polyol but without fillers. During the foaming process, the maximal temperatures reached by PU foams were not affected by the presence of 1 to 7% of microspheres or nanoclay, but slightly lower than the control. In addition, foams with fillers displayed roughly the same thermal conductivity as soy-polyol based foams without fillers.

Physical Properties of Soy-Phosphate Polyol-Based Rigid Polyurethane Foams

Water-blown rigid polyurethane (PU) foams were made from 0–50% soy-phosphate polyol (SPP) and 2–4% water as the blowing agent. The mechanical and thermal properties of these SPP-based PU foams (SPP PU foams) were investigated. SPP PU foams with higher water content had greater volume, lower density, and compressive strength. SPP PU foams with 3% water content and 20% SPP had the lowest thermal conductivity. The thermal conductivity of SPP PU foams decreased and then increased with increasing SPP percentage, resulting from the combined effects of thermal properties of the gas and solid polymer phases. Higher isocyanate density led to higher compressive strength. At the same isocyanate index, the compressive strength of some 20% SPP foams was close or similar to the control foams made from VORANOL 490.

Isocyanate Reduction by Epoxide Substitution of Alcohols for Polyurethane Bioelastomer Synthesis

A phosphate ester-forming reaction was carried out by mixing epoxidized soybean oil with up to 1.5% o-phosphoric acid. In situ oligomerization took effect almost instantly producing a clear, homogeneous, highly viscous, and a low-acid product with a high average functionality. The resulting epoxide was used as a reactant for urethane bioelastomer synthesis and evaluated for rigid foam formulation. Results have shown that with a number of catalysts tested phosphoric acid significantly enhances a solvent-free oxirane ring cleavage and polymerization of the epoxidized soybean oil via phosphate-ester formation at room temperature. The resulting phosphoric acid-catalyzed epoxide-based bioelastomer showed an 80% decrease in extractable content and increased tensile strength at the same isocyanate loading relative to the noncatalyzed epoxide. The oligomerized epoxidized soybean oil materials exhibited ASTM hydroxyl values 40% less than the nonoligomerized starting material which translates to reduced isocyanate loadings in urethane applications.

Physical Properties of Soy-polyol Based Polyurethane Foams Reinforced with Microspheres and Nanoclay

This study investigated the effect of incorporating microsphere and nanoclay fillers from 1-7% on the physical properties of polyurethane (PU) foams made from a polyol containing 15% soybean oil based polyol. With increasing filler percentage, the PU foam volume increased because these fillers provided surfaces for nucleation and more gas bubbles were generated during the foaming process. The compressive strength of PU foams decreased slightly when increasing the microsphere content from 1 to 3% and then increased when the filler was higher than 3% . At 7% microsphere content, the foams displayed the same compressive strength as the control foams made from 100% petroleum polyol. For PU foams reinforced with nanoclay, their compressive strength changed little from 1 to 5%, but decreased at 7% due to a lower density. Foams containing 5 to 7% microspheres or 3 to 7% nanoclay had density-compressive strength comparable or superior to the control. SEM was used to observe the morphology of reinforced foams. Foams reinforced with fillers had more cells and smaller cell size than foams made from 15% soy-polyol but without fillers. During the foaming process, the maximal temperatures reached by PU foams containing were not affected by the presence of 1 to 7% of microspheres or nanoclay, but slightly lower than the control. In addition, foams with fillers displayed roughly the same thermal conductivity as soy-polyol based foams without fillers.