The preparation and properties of some urethane foams from castor oil and elaidinized castor oil

Summary The preparation and properties of two series of castor oil urethane foams, one from castor oil and the other from elaidinized castor oil, were investigated. The first series of foams was made from prepolymers containing 60% of castor oil prepared at increasing temperature levels to vary the degree of crosslinking in the final foams. These foams had lower tensile strengths than observed for a previously prepared foam of 60% castor oil and did not show significant differences in water resistance as crosslinking varied. They were increased nearly 100% in compressive strength with increased crosslinking and had very good shrinkage characteristics as values of only 1 to 2% were obtained. A second series of foams was prepared from 50, 60, 70, and 80% of elaidinized castor oil to compare with foams from a similar series from castor oil. This series of foams of 50 to 80% elaidinized castor oil contents was similar in density (1.7 to 6.7 lbs./cu. ft.), had improved shrinkage characteristics (11, 1, 3, and 4%, respectively), showed increased compressive and tensile strengths (up to 12.1 p.s.i. at 50% compression modulus and 34.7 p.s.i. ultimate tensile for the 60% foam formulation), and had better water-resistance properties (411 to 155%vs. 515 to 170% water absorption) than the analogous foams from castor oil. In general, humid aging only slightly affected the values obtained for the foams and was significant in only a few instances,e.g., decreased tensile in the elaidinized castor oil series. Thus increasing crosslinks in the foam apparently did not improve water resistance but did improve shrinkage characteristics in addition to some increased strength properties, as would be anticipated. Foams from elaidinized castor oil, while similar in density and foaming characteristics to analogous foams from castor oil, exhibited less shrinkage and improved water-resistance. Presented at the 50th Annual Meeting of the American Oil Chemists' Society, New Orleans, La., April 20–22, 1959. Ono of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Synthesis and characterization of castor oil urethane triamine networks

Castor oil was polymerized with diisocyanate and crosslinked with primary triamine (Jeffamine T-403) to form networks. The effect of triamine as a crosslinking agent on rubbery castor oil urethane elastomer was determined by measuring network parameters such as average molecular weight between crosslinks (MC) number of polymer chains per unit volume (N), tensile strength, and modulus of the networks. The crosslinking density was varied by varying the ratio of NCO : NH₂ from 0.60 to 0.95. The results indicated the formation of highly crosslinked elastomers at all NCO : NH₂ ratios employed. The tensile stregth and modulus increased with increasing crosslink density up to a value of NCO : NH₂ 0.85 and after this there was no significant change, indicating the maximum limit of improvement attainble in terms of network characteristics.     

Simultaneous interpenetrating networks based on castor oil elastomers and polystyrene. V. Behavioral trends and analysis

The morphology and/or mechanical properties of simultaneous interpenetrating networks, SINs, based on castor oil elastomers and crosslinked polystyrene, were studied by electron microscopy, stress–strain analysis, and/or Izod impact tests. Several synthetic details were changed systematically and the concomitant changes in morphology or particular properties observed. The toughness of elastomer SINs increased with decreasing domain size of the polystyrene dispersed phase. The use of a prepolymer for the elastomer network synthesis promotes the formation of larger polystyrene domains. The impact resistance of the SINs increased with the total elastomer content. Properly crosslinked and postcured compositions developed impact energies of about 60–70 J/m. SINs based on castor oil-derived elastomers and crosslinked polystyrenes form prototype engineering materials which already compared satisfactorily to commercial polymers in terms of mechanical behavior.     

Castor polyols for urethane foams

Summary A systematic investigation of some 21 castor polyols as base materials for preparing urethane foams was carried out. Prepolymers were prepared both from individual castor polyols and from mixtures of them with an anhydrous castor oil. Foams formed from these prepolymers were checked for shrinkage on cure, density, and modulus. From the wide range of results obtained it is evident that castor polyols can serve as effective urethane components. Aside from serving as major polyols for reaction with di-isocyanates, they can also be used as modifying polyols a) to speed up prepolymer preparation, b) to adjust prepolymer viscosity to any required degree, c) to minimize loss of modulus on humid aging, and as cross-linking centers with negligible loss of foam modulus. Details covering the preparation of a nonshrinking, semi-rigid, light-weight urethane foam based on an 85% anhydrous castor oil/15% epoxidized castor oil mix are outlined in the article. Presented at the Spring Meeting, American Oil Chemists' Society, Memphis, Tenn., April 20–23, 1958.     

Simultaneous interpenetrating networks based on castor oil polyesters and polystyrene

Simultaneous interpenetrating networks (SIN's) have been synthesized by simultaneous polymerization of a rubbery polymer based on castor oil and a second plastic forming monomer plus initiator and crosslinking agent. According to the overall composition and synthetic details, SIN's of elastomeric, leathery, or plastic behavior have been obtained. Polymers employed were the crosslinked polyester from castor oil and sebacyl chloride (a castor oil derivative) and polystyrene crosslinked with 1 percent divinyl benzene, simultaneously polymerized. Electron microscopy revealed a complex two phase morphology strongly depending on the relative gelation times of the two polymers, the polymer gelling first becoming the more continuous phase. Stress-strain curves show a SIN plastic with a well developed yield point, as well us highly toughened elastomers. Both the plastic and the elastomeric SIN's are tougher than the corresponding homopolymers. Modulus-temperature curves show a glass transition temperature around ?60°C for the elastomer component, and +100°C for the polystyrene in the SIN's.     

Correlation of mechanical property,crosslink density and thermogravimetric behavior of castor oil polyurethane–polystyrene divinyl benzene simultaneous IPN networks

Several simultaneous interpenetrating networks (IPN) of castor oil polyurethane (COPUN) and polystyrene divinyl benzene (PSN) were synthesized under conditions where the free radical polymerization of styrene and the crosslinking reaction of castor oil and toluene diisocyanate progress at comparable rates. Comparison of the mechanical properties and crosslink density of the COPUN and COPUN/PSN-IPNs indicates a marginal increase in tensile strength and crosslink density from COPUN to 60COPUN/40 PSN IPN. IPN samples prepared with further increased PSN content show steady decrease in the above properties. This reversal of the expected trend was attributed to the possible greater molecular interpenetration achieved due to similar gelation times with resultant extension of chains and increase in free volume between crosslinks. This was further confirmed from thermogravimetric data on the initial stages of decomposition of the IPNs.     

Simultaneous interpetrating network based on castor oil elastomers and polystyrene. III. Morphology and glass transition behavior

Electron microscopy and dynamic mechanical spectroscopy (DMS) techniques were used to study the morphology and glass transition behavior of simultaneous interpenetrating networks (SIN's), based on three different castor oil derived elastomers, and polystyrene (PS) plastic erosslinked with 1 percent divinyl benzene. The castor oil elastomers consisted of either the sebacic acid polyester, 2,4-tolylene diisocyanate polyurethane, or the mixed poly(ester-urethane). Emphasis was placed on two compositions having 10 and 40 percent elastomer contents by weight of each type, the remainder being PS. In all cases, a two-phase morphology emerged. With the 10 percent elastomer composition, the use of vigorous stirring during the early stages of reaction resulted in materials having the crosslinked polystyrene as the continuous phase and elastomer domains (ranging from 100 to 8000 nm in size) as the discontinuous phase. The elastomer domains contained a polystyrene cellular structure, with the polystyrene cell sizes ranging from 50 to 300 nm size. Several examples showed morphologies resembling high impact polystyrene. Materials having a 40 percent elastomer content always showed a continuous phase of castor oil elastomer, with the PS displaying a bimodal size cellular structure. Domain sizes ranged from 10 to 860 nm. The DMS studies showed two well-defined glass transitions near their respective homopolymer glass transitions, but shifted inwards to greater or lesser extents indicating some molecular mixing between the two polymers. The glass transition of the pure elastomer phase occurred at ?66°C for the castor oil polyester elastomer, ?4°C for the castor oil polyurethane elastomer and ?50°C for the castor oil poly(ester-urethane) elastomer. Phase separation in these materials is postulated to occur by two mechanisms: (1) multiple precipitation of polystyrene chains at progressive levels of polymerization and (2) microsyneresis processes. The thermodynamics of mixing and phase separation in polymerizing SIN's is examined in some detail.     

Ecofriendly Autoxidation of Castor Oil/Ricinoleic Acid. Multifunctional Macroperoxide Initiators for Multi Block/Graft Copolymers

Ecofriendly autoxidation is a reaction of air oxygen with unsaturated organic molecules at room temperature. Castor oil and ricinoleic acid were ecofriendly autoxidized for 5 months to obtain castor oil macroperoxide with a Mn of 1935 g mol⁻¹ (Pcast5m) and the ricinoleic acid macroperoxide initiator (Prici5m) with a Mn of 1169 g mol⁻¹. Peroxide groups thermally initiated the free radical polymerization of methyl methacrylate (MMA), n-butyl methacrylate (nBMA), and styrene (S). Peroxide formation in the oxidized castor oil and ricinoleic acid was confirmed using iodometric analysis, elemental analysis, and differential scanning calorimetry technique. Peroxide decomposition in both macroperoxide initiators was observed at 166 °C for Prici5m and 170 °C for Pcast5m. Hydroxyl groups of Pcast5m were reacted with methacryloyl chloride to obtain methacrylated castor oil macroperoxide (PcastMA). The polymerization rates of the obtained macroinitiators were compared. The polymerization rate order is Pcast5m > Prici5m > PcastMA. Polymerization of styrene by PcastMA resulted in an increase in molar masses and an increase in the polymerization time while those of the styrene polymerization by Pcast5m and Prici5m remained constant. Carboxylic acid groups were reacted with amine-terminated polyethylene glycol (PEG), polydimethyl siloxane (PDMS), and polytetrahydrofuran (PTHF) while the hydroxyl functionality initiated the ring-opening polymerization of ε-caprolactone (CL). Prici-PEG-PMMA, Prici-PS-PDMS, Prici-PS-PTHF, Pcast-PS-PCL, Pcast-PCL-PMMA, and Pcast-PS-PnBMA multiblock copolymers were prepared and characterized using spectrometric, thermal, and stress–strain measurement techniques.     

Thermal and mechanical characterization of maleimide‐functionalized copoly(urethane‐urea)s

Maleimide functionalized copoly(urethane‐urea)s were prepared by the reaction of a binary mixture of dibenzyldiisocyanate and 5‐maleimidoisophthalic diisocyanate with a macrodiol (PEGA‐2000), using diethylene glycol and trimethylol‐propane as chain extender and crosslinkers in toluene‐dichloromethane solutions at the ratio NCO/OH = 1.2. Structures of polymers were confirmed by IR spectroscopy and properties were studied by thermal and mechanical analysis (dynamic mechanical analysis (DMA), differential scanning calorimetry, thermogravimetric analysis, stress‐strain) and other physical methods. Maleimide modification increased the storage modulus and Young's modulus of copoly(urethane‐urea)s, slightly increased their glass transition temperature from ?10.6°C to ?6.3°C. Copoly(urethane‐urea) networks obtained by thermal polymerization of maleimide functions showed significantly increased of the mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Castor oil based interpenetrating polymer networks. II. Synthesis and properties of emulsion polymerized products

Polystyrene Latexes were synthesized using sodium ricinoleate (the ehief saponification product of castor oil) as the surfactant. Later sulfur, more sodium ricinoleate, and sometimes castor oil were added, and the emulsion heated to a temperature where the sulfur vulcanized the castor oil products, making a semi-interpenetrating polymer network. Stress-strain studies showed the presence of a well developed yield point and high elongation for some samples, indicating considerable toughening for slow rates of strain. Electron microscopy revealed a complex two-phased morphology. Usually polystyrene was the continuous phase. The rubbery phase domain size depended upon the amount of castor oil products added lzod impact strengths showed only modest improvements; probably because of the high glass transition temperature of the castor oil vulcanizate.     

Block polymers from poly(ethylene oxide) and styrene

Block copolymers containing poly(ethylene oxide) and polystyrene segments were synthesised via chemical reactions. A step-wise procedure was first employed to prepare peroxycarbamates which were later used to initiate free radical polymerization of styrene at elevated temperatures. In some runs the polymerization temperature and time were programmed. Styrene contents, molecular weights, elastic modulus—temperature relationships, impact strengths and stress—strain behaviour of the copolymers were determined.     

Behavior of polyoxyethylene‐containing interpenetrating polymer networks and their LiCLO4 complexes as phase transfer catalysts and ionic conductors

Simultaneous grafted interpenetrating polymer networks (IPNs) based on [castor oil–poly(ethylene glycol) (PEG)] polyurethane and poly(alkyl methacrylate) were synthesized by simultaneously coupling castor oil and PEG with 2,4‐toluene diisocyanate and by radical polymerization of alkyl methacrylate with castor oil. The gel content of the IPNs is ～96% in most cases. The IPNs were characterized by infrared spectroscopy. The effects of compositional variation of the IPNs on phase transfer catalytic efficiency and mechanical properties, and conductivity of the IPNs complexed with LiClO₄ were also studied. The results show that the IPNs have good phase transfer catalytic ability in the Williamson reaction and exhibit a maximum conversion of potassium phenolate at 55% polyoxyethylene (PEO). The phase transfer catalytic ability of the IPN increases with molecular weight of PEG used in the IPN synthesis and with the length of alkyl groups of the grafts, but decreases with increasing crosslinking degree. The complex of the IPNs with LiClO₄ exhibits good ionic conductivity at room temperature in the range 10^?5–3 × 10^?4 S/cm. This ionic conductivity decreases with increasing either the crosslinking degree or the molecular weight of PEG used, but increases with increasing PEO content. The more compatible are the grafts with PEO, the lower is the conductivity. Either butyl methacrylate or ethyl methacrylate is a good choice for the monomer in the synthesis of the IPNs for use as phase transfer catalysts and ion conducting materials. The IPNs showed high tensile strength in the range 10–20 MPa. The good mechanical properties of the IPNs favor their applications as a strong solid polymer electrolyte film and an easily recoverable phase transfer catalyst. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 830–836, 2003     

Interpenetrating polymer networks from castor oil-based polyurethanes and polystyrene,XXV

Interpenetrating polymer networks (IPNs) of castor oil-based polyurethanes and polystyrene were prepared by simultaneous polymerization. The liquid prepolyurethanes were formed by reacting the hydroxyl functionality of castor oil with isophorone diisocyanate using different stoichiometric NCO/OH ratios. These prepolyurethanes were mixed with styrene monomer and subsequently polymerized by free radical polymerization initiated by benzoyl peroxide in the presence of the crosslinker 1,4-divinyl benzene. The interpenetrating polymer networks. PU/PS IPNs, were obtained as tough and transparent films by the transfer moulding technique. These IPNs were characterized by the static mechanical properties (tensile strength, Young's modulus and % elongation), thermal properties and morphology. The dielectric relaxation properties (σ, E′, E″ and tanδ) of the IPNs at different temperatures were studied.     

Castor oil based interpenetrating polymer networks,IV. Mechanical behavior

The physical and mechanical properties of interpenetrating polymer networks (IPN's) based on castor oil-urethane and polystyrene are detailed in this paper. Dynamic mechanical spectroscopy showed extensive but incomplete molecular mixing of the two polymers. The glass transition temperatures of the IPN's gradually merged from two distinct transitions into one broad transition at an intermediate temperature as the crosslink level of the castor oil component was increased. At low polystyrene contents, the IPN's yielded stress-strain behavior similar to reinforced elastomers, but at high polystyrene contents, they exhibited increased elongation. For example, the latter materials showed well developed yield points. Stress whitening and necking were also observed, suggesting a possible failure mechanism by crazing. Cold drawing was exhibited by the materials under tension. The tensile strength and Young's modules were enhanced as the polymer II (polystyrene) content was increased at constant crosslink level of polymer I (castor oil-urethane). A similar effect was also observed by maintaining the polystyrene content constant but increasing the crosslink level of polymer I. The impact strength of the materials ranged from 32.1 to 53.4 N · m/m, which is approximately two to three times that of homopolymer polystyrene. The best materials were those with compositions in the range of 40-46 percent castor oil-urethane. The materials prepared by using tolylene diisocyanate as crosslinker for the castor oil phase had the best impact properties, especially at an NCO/OH ratio of 0.95.     

Toughened composites prepared from castor oil based polyurethane and soy dreg by a one‐step reactive extrusion process

A series of water‐resistant composites were successfully prepared from a mixture of soy dreg (SD), castor oil, and 2,4‐toluene diisocyanate (TDI) by a one‐step reactive extrusion (REX) process. The structure and properties of the composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile testing, and swelling experiments. The results indicated that the toughness of the composites prepared from castor oil based polyurethane and SD was significantly improved. In this case, TDI played an in situ compatibilization role through the crosslinking reaction of ? NCO groups with ? NH₂, ? NH? , and ? OH groups in SD and castor oil. With an increase in the molar ratio of ? NCO groups of TDI and ? OH groups of castor oil, the degree of crosslinking, tensile strength, glass‐transition temperature, water resistivity, and solvent resistivity of the composites increased. With an increase in the SD content of the composites, the tensile strength and solvent resistivity of the composites increased because of the reinforcement of the cellulose component in SD. This work provided a simple and effective way of preparing SD‐based composites by a REX process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 953–960, 2006     

Effect of the doses and nature of vegetable oil on carbon black/rubber interactions: Studies on castor oil and other vegetable oils

The effects of additives in various vegetable oils on the physical, mechanical, and adhesion properties of carbon black/rubber compounds were studied. Various doses of castor oil and some other oils such as paraffin oil, vegetable oil 1, and cashew nut shell liquid (CNSL) at a fixed dose (1 phr) were used. With an increase in the castor oil content, the modulus, tear strength, and tensile strength increased, whereas the hardness and adhesive strength exhibited little variation up to 1 phr. Beyond 1 phr castor oil, the modulus, tear strength, and hardness decreased, whereas the adhesive and tensile strengths increased up to 2.5–3 phr and then decreased. Therefore, castor oil seemed to behave as a coupling agent up to 1 phr and as a coupling agent and a plasticizer in the range of 1–3 phr; beyond that, the main role of castor oil was plasticization. When various oils at a fixed dose (1 phr) were compared, it was found that the vegetable oils exhibited enhanced properties in comparison with those of paraffin oil. In addition, both of the unsaturated oils (castor oil and vegetable oil 1) enhanced physical and mechanical properties in comparison with saturated paraffin oil. CNSL exhibited the best adhesion properties against mild steel and galvanized iron substrates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1574–1578, 2003     

Photocuring and thermomechanical properties of multifunctional amide acrylate compositions derived from castor oil

The photopolymerization of multifunctional acrylate monomers synthesized from castor oil was investigated by photo-DSC. These studies revealed that the extent of photopolymerization depended on the double bond concentration and a greater degree of crosslinking occurred in monomer mixtures with higher difunctional content. The monomer mixtures displayed significantly higher maximum rate of polymerization (R_p^max) and shorter time to reach peak maximum than the pure monomers. DMTA studies of films showed good storage modulus and broad tan δ transitions indicating heterogeneity in the crosslinked networks. The films displayed sub-T_g transitions in the loss modulus curves were possibly due to the side chain motions of the monomer acrylates which increased with increasing triacrylate concentration. Glass transition temperature (T_g) of these networks depended on composition and shifted to higher values with increasing amount of triacrylate.     

Swelling and network parameters of high oil‐absorptive network based on 1‐octene and isodecyl acrylate copolymers

Crosslinked 1‐octene‐isodecyl acrylate copolymers were synthesized and evaluated for oil‐absorbency applications. The copolymer was crosslinked at different concentrations of ethylene glycol diacrylate (EGDA) and EG dimethacrylate (EGDMA) crosslinkers via catalytic initiation or by electron‐beam irradiation at a dose rate 80 kGy. The concentration of both crosslinkers was varied from 0.5 to 2%. The effects of the crosslinking conditions such as crosslinker concentration, method of polymerization and monomer concentrations on the conversion and gel fraction were examined through oil‐ absorption tests using petroleum crude oil. It was found that the oil absorbency was influenced mainly by the degree of crosslinking and the hydrophobicity of the copolymer units. The final equilibrium oil content, volume fraction of the polymer, and swelling capacity were determined at 298 K. The effective crosslinking density, average molecular weight between the crosslinks, and polymer–toluene interaction parameter were determined from stress–strain measurements. The crosslinking efficiencies of EGDA and EGDMA toward copolymers were determined. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 80–91, 2005     

Characterization of crosslinked polystyrene beads and their composite in SBR matrix

Monodisperse crosslinked polystyrene (PS) beads were prepared by a reaction of semibatch emulsion polymerization with styrene monomer, divinylbenzene (DVB) crosslinking agent, and potassium persulfate (K₂S₂O₈) initiator in the absence of emulsifier. The glass transition temperature (T_g) and the mean diameter of the beads were increased from 100 to 135°C and from 402 to 532 nm, respectively, for an incorporation of 2–10 mol % DVB. Crosslinking density was also linearly increased with DVB content. Scanning electron microscopy (SEM) photographs of styrene–butadiene rubber (SBR) composite filled with various contents of PS beads revealed that PS beads are relatively well dispersed without changing the spherical shape of the beads in all ranges of compositions. In stress–strain analysis, elongation at break and tensile strength of SBR composite were increased with the bead content. Applicability of the PS beads as a filler in SBR matrix is tested by plotting Mooney–Rivlin or Guth–Smallwood equations. However, mechanical properties of the composite with the beads were not so excellent as those of the composite with carbon black. Crosslinked PS beads are still tentative as a white color reinforcing filler on the SBR matrix. © 1995 John Wiley & Sons, Inc.     

Preparation and properties of urethane alkyd based on a castor oil/jatropha oil mixture

Castor oil is the only major natural vegetable oil that contains a hydroxyl group and so it is widely used in many chemical industries, especially in the production of polyurethanes. In this work, castor oil was interesterified with jatropha oil and the product was subsequently reacted with toluene diisocyanate to obtain urethane alkyd. The prepared urethane alkyd was characterized and its properties were determined and compared with those of the conventional (glycerol/jatropha oil) and commercial urethane alkyds. The castor oil/jatropha oil-based urethane alkyd had a lower molecular weight and viscosity, a slightly lower hardness and greatly longer drying time than the conventional and commercial urethane alkyds, but otherwise the film properties were broadly similar, including being very flexible, with an excellent adhesion and high impact resistance. In addition, they also exhibited excellent resistance to water and acid.