Soy-based Polyurethane Research Articles

Fiber reinforced soy-based polyurethane spray foam insulation. Part 1: Cell morphologies

Environmentally friendly polyurethane (PU) spray foam insulation was prepared by substituting petrochemical polyol with soy-based polyol. The effects of adding wood fiber and water on the cell morphologies were studied. Cell size increased with the presence of wood fiber, but it decreased with an increase of water (H2O). Still, shorter fiber decreased in foam density but increased in cell size and open cell content.

Fiber reinforced soy-based polyurethane spray foam insulation. Part 1: Cell morphologies

Environmentally friendly polyurethane (PU) spray foam insulation was prepared by substituting petrochemical polyol with soy-based polyol. The effects of adding wood fiber and water on the cell morphologies were studied. Cell size increased with the presence of wood fiber, but it decreased with an increase of water (H2O). Still, shorter fiber decreased in foam density but increased in cell size and open cell content.

Synthesis of Soy-Polyol by Two Step Continuous Route and Development of Soy-Based Polyurethane Foam

Soy-polyol has been synthesized via a low energy two-step continuous route thus avoiding intermediate steps and chemicals. The functional groups of soy-polyol thus produced were identified by Fourier transform infrared (FTIR) spectroscopy which confirmed the cleavage of the double bonds, the formation of new epoxy linkages and the presence of hydroxyl groups. The change in chemical structure and physical properties of the soy polyol was further characterized and the results indicated a successful conversion with reduced unsaturation, increased hydroxyl number and increased viscosity. Polyurethane foam was prepared from soy-polyol using isocyanate and thermogravimetric analysis was used to study its thermal decomposition behaviour. Multiple transitions were identified in relation to depolymerization and bond dissociation. Density and compressive strength of the soy-foam were found to be satisfactory. An investigation of microstructure of soy foam by scanning electron microscope and X-ray computed tomography revealed the internal cell morphology and cell structure.

Development of Flax Fiber/Soy-Based Polyurethane Composites for Mass Transit Flooring Application

In this study, soy-based polyurethane foam was reinforced with random oriented flax fiber to create green composite paneling. This paneling can be used as replacement for plywood in mass transit flooring. To establish optimal material properties, the flax/foam composite's density was modified through manipulation of both fiber volume fraction and foam void content in order to determine processing modification upon mechanical performance. Both static flexural testing and dynamic low velocity impact was performed. Mechanical characterization was performed by both flexural testing and screw fastener pullout studies. Resultant properties demonstrate the feasibility of lower maintenance renewable composite materials as replacement for current transit flooring.

Soy-Based Polyurethane Foam Reinforced with Carbon Nanotubes

The objective of this research is to develop soy-based polyurethane (PU) foam product reinforced with carbon nanotubes. The shortage of petroleum and the increasing concern on environmental issues have resulted in an interest in using renewable substances as building blocks for polymer applications. Multi-walled carbon nanotube (MWNT) was used in this study to reinforce the soy-based polyurethane foam. The compressive and mechanical properties of the composites were enhanced with adding carbon nanotubes. Neat polyurethane was used as a control. Soy-based polyurethane / carbon nanotubes composites with loadings of 0.5 and 1.0 wt% were fabricated. The compressive, flexural, and tensile properties of MWNTs-PU foams were improved by 24, 30 and 30 %, respectively, as compared with the neat PU foam. The greatest enhancements on compressive and flexural properties were shown at the 0.5 wt% MWNT loading, while the highest tensile stress enhancement of PU foam was shown at 1 wt% MWNT loading.

Synthesis and thermal properties of soybean oil-based waterborne polyurethane coatings

Waterborne polyurethane coatings were prepared by a polyaddition reaction using toluene diisocyanate (TDI), 2,2-di(hydroxy-methyl) propionic acid, soy-based polyols with different hydroxyl values, plus 2-hydroxyethyl methacrylate (HEMA) as chain termination agent, triethylamine as neutralization agent, and DBTDL as catalyst. Six soybean oil-based polyols were used in this study with hydroxyl values of 100, 115, 128, 140, 155, and 164 mg KOH g−1, respectively. The molar ratio of polyol hydroxyl to DMPA was varied from 1.6 to 2.6. The storage stability of the waterborne polyurethane coatings was greater than 6 months. The thermal properties of the coating films were investigated by TG and DCS. The results show that the soy-based polyurethane films decomposed in three stages. The glass transition temperatures, T g, of the soy-based polyurethane films increased with the hydroxyl number of the soy-based polyol.

<p>Bio-based Nanocomposites: An Alternative to Traditional Composites</p>

Polymer matrix composites (PMC), often referred to as fiber reinforced plastics (FRP), consist of fiber reinforcement (E-glass, S2-glass, aramid, carbon, or natural fibers) and polymer matrix/resin (polyester, vinyl ester, polyurethane, phenolic, and epoxies). Eglass/polyester and E-glass/vinyl ester composites are extensively used in the marine, sports, transportation, military, and construction industries. These industries primarily use low-cost open molding processes, such as manual/spray lay-up. Polyester and vinyl ester resin systems produce styrene emissions. Because of the stringent EPA regulations on styrene emissions, composite manufacturers are interested in using low-cost closed molding processes, such as vacuum-assisted resin transfer molding (VARTM) and styrene-free resin systems such as non-foam and full-density polyurethanes (PUR). Polyurethanes are polymers created by addition of polyisocyanates and polyols. The polyol component in polyurerhane can be produced from soybean oil. This study demonstrates that with the proper addition of nanoparticles, mechanical properties of soy-based polyurethane can be enhanced. These nanomodified soy-based polyurethane/glass composites manufactured by using the low-cost VARTM process provide alternatives to traditional glass/polyester and glass/vinyl ester composites. These composites will be more environmental friendly for two reasons: (a) Polyurethane does not produce styrene emission, thereby, resulting in a safer work place and (b) Polyol is made from a renewable resource (soybean oil).

Characterization of soy-based polyurethane networks prepared with different diisocyanates and their blends with petroleum-based polyols

Raw soybean oil was hydroxylated with acetic acid and hydrogen peroxide to prepare soy-based polyols of various functionalities. These polyols were reacted with a modified diphenyl methane diisocyanate (Isonate 143L) to make polyurethane networks. The sol fractions decreased as the hydroxyl number of the polyol increased, and the glass-transition temperatures increased with the hydroxyl number, as did the rubbery plateau storage modulus and Young's modulus of the networks. When the glass-transition temperatures of each network were plotted as a function of the polyol's hydroxyl number, a linear relationship was observed over the range investigated. This trend closely matched that of our previous work with soy-based polyurethane networks. A second series of networks was prepared with the same polyols but with different isocyanates. The nature of the crosslinker was shown to somewhat influence the sol fractions, glass-transition temperatures, and stress–strain behavior of the networks. A linear relationship was recorded between the storage modulus at 125°C of a network and the average functionality of the polyol from which it was synthesized. Finally, two separate polyurethane networks were prepared through the blending of two polyols: one based on petroleum and the other based on soy. These networks were also characterized, and the compatibility of each blend was addressed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Thermal stability of soy-based polyurethanes

New types of polyurethanes were prepared by reacting diisocyanates and formiated soy polyols with different OH functionalities. Thermal properties and degradation kinetics were investigated by TGA. All prepared PU's showed at least two-weight loss steps, the first one, around 210 °C. Thermal stability of these PUs depends strongly on urethane groups per unit volume and an increase in the weight loss was observed as a result of the increased amount of urethane groups. Degradation kinetics behavior of the soy-based polyurethanes was investigated according to the Flynn method. Different average activation energy values were obtained from isothermal and isoconversional curves, 140.6 KJ/mol and 62.8 KJ/mol, respectively, indicating the complexity of the PUs degradation process.

Structure and Properties of Polyurethanes Prepared from Triglyceride Polyols by Ozonolysis

Ozonolysis was used to obtain polyols with terminal primary hydroxyl groups and different functionalities from trilinolein (or triolein), low-saturation canola oil, and soybean oil. The functionality of the model polyol from triolein (trilinolein) was 3.0 and that of soy polyol was 2.5, due to the presence of unreactive saturated fatty acids, while canola gave a polyol with a functionality of 2.8. All polyols exhibited a high tendency to crystallize at room temperature. The resulting waxes had melting points comparable to that of paraffin and very low viscosities in the liquid state. The polyols were cross-linked using 4,4'-methylenebis(phenyl isocyanate) to give polyurethanes. Glass transitions (T(g)) for the model-, canola-, and soy-based polyurethanes were 53, 36, and 22 degrees C, respectively. The about 30 degrees C lower T(g) of the soy-based polyurethane than that of the model polyurethane was the result not only of lower functionality but also of the presence of saturated fatty acids in the former. Polyurethane from the canola polyol had intermediate cross-linking density and properties. These polyurethanes displayed excellent mechanical properties and higher glass transition temperatures compared to polyurethanes from epoxidized and hydroformylated polyols of the same functionality, presumably due to the absence or lower content of dangling chains in the former.

Thermal and mechanical properties of glass reinforced soy-based polyurethane composites

Two series of polyurethane resins were prepared using Soypolyol 204 derived from soybean oil and petrochemical polyol Jeffol G30-650. Polyurethanes from soybean oil have good thermal, oxidative and weather stability, and can be used as a matrix in composite materials. The objective of this study was to compare the mechanical properties of untreated E-glass fiber reinforced composites prepared with soybean oil-based polyurethanes to that of the petrochemical polyol based ones. The effect of the polyurethane resin on physical and mechanical properties was studied. The results showed that mechanical properties such as tensile and flexural strength, tensile and flexural modulus of the Soypolyol based composites were comparable with those from composites based on petrochemical polyol. Since soy-based polyurethanes offer better thermal, oxidative and hydrolytic stability than petrochemical based ones, they could be a viable alternative to the petrochemical urethane matrix resins for composites.

Laminates From The Soy-Based Polyurethanes and Natural and Synthetic Fibers

ABSTRACTTwo polyols were prepared from soybean oil, one by epoxidation route and the other via hydroformylation. The polyol obtained by epoxidation has secondary groups and has a gel time of more than one hour when reacted with crude MDI to produce polyurethanes. Hydroformylated polyol has a gel time with MDI of several minutes and is more suitable for reinforced reaction injection molding (RRIM). The first group of polyurethanes had a glass transition close to 80 °C while the hydroformylated gave about 30 degrees lower Tg and comparable strength but higher elongation. Adding glycerin as the crosslinker could increase both Tg and strength. Two series of laminates were prepared using several types of glass fabric, carbon fiber, polyester, cotton and jute fabrics r as reinforcements. Hydroformylated polyol based polyurethane composites were softer, with lower Tg, modulus and strength. Composites with organic fibers were lighter and more flexible than the glass reinforced samples. For comparison glass reinforced epoxy and polyester were prepared and tested. Organic fibers gave lower stiffness and strength than the corresponding glass or carbon fiber. Although the neat polyester and epoxy resins had somewhat higher strengths than the polyurethanes from soybean oil, mainly due to the higher crosslinking density, the composites from the soy oil-based resin displayed comparable or better properties. Glass transition and mechanical properties of the soy-based polyurethanes was varied from about 70 °C to 140 °C with added crosslinkers. Processing time of the soy-polyurethanes resins was shorter than that of the other two resins.