STUDY ON CASTOR OIL POLYURETHANE/POLY (METHYL METHACRYLATE) AB CROSSLINKED POLYMERS

Castor oil polyurethane/poly(methyl methacrylate) AB crosslinked polymers (ABCP) were synthesized by free radical copolymerization of MMA and vinyl-terminated castor oil polyurethane which was obtained from isocyanate-terminated castor oil polyurethane and hydroxyethyl methacrylate The mechanical properties, transition and relaxation, as well as compatibility and morphology of the ABCP were investigated by changing the component. The results show that the ABCP is a semicompatible system and the compatibility of the two components decreases with increasing content of the hard segment. The mechanical and damping properties of the ABCP are obviously superior to that of their homopolymers. The damping value is mainly controlled by cross[ink density of the ABCP but the T-g value by component.     

巯基-烯光点击反应辅助合成多官能度蓖麻油基聚氨酯丙烯酸酯

研究巯基-烯光点击反应辅助合成多官能度蓖麻油基聚氨酯丙烯酸酯。首先通过光引发的巯基-烯点击反应,于蓖麻油分子上引入巯基乙醇,形成多羟基化合物,然后加入丙烯酸羟丙酯与异佛尔酮二异氰酸酯,以物质的量为1:1反应得到端异氰酸酯丙烯酸酯,最终得到蓖麻油基聚氨酯丙烯酸酯。通过调节羟基含量可以得到不同官能度的丙烯酸酯。采用红外光谱、核磁氢谱、热重分析等手段表征其结构和性能,并测试了合成的聚氨酯丙烯酸脂的吸水率、附着力等性能,同时考察了它的热稳定性。结果表明, 在紫外光照射下,巯基和不饱和双键之间发生了加成反应;该聚合物的固化膜性能得到提高,尤其是硬度和热稳定性。由本文快速合成方法得到的树脂性能良好,具有较好的应用前景,扩大了巯基-烯光点击反应在高性能UV固化材料方面的应用范围。     

The study of mechanical behavior and flame retardancy of castor oil phosphate-based rigid polyurethane foam composites containing expanded graphite and triethyl phosphate

The goal of this work was the synthesis of novel flame-retarded polyurethane rigid foam with a high percentage of castor oil phosphate flame-retarded polyol (COFPL) derived from renewable castor oil. Rigid flame-retarded polyurethane foams (PUFs) filled with expandable graphite (EG) and diethyl phosphate (TEP) were fabricated by cast molding. Castor oil phosphate flame-retarded polyol was derived by glycerolysis castor oil (GCO), H₂O₂, diethyl phosphate and catalyst via a three-step synthesis. Mechanical property, morphological characterization, limiting oxygen index (LOI) and thermostability analysis of PUFs were assessed by universal tester, scanning electron microscopy (SEM), oxygen index testing apparatus, cone calorimeter and thermogravimetric analysis (TGA). It has been shown that although the content of P element is only about 3%, the fire retardant incorporated in the castor oil molecule chain increased thermal stability and LOI value of polyurethane foam can reach to 24.3% without any other flame retardant. An increase in flame retardant was accompanied by an increase in EG, TEP and the cooperation of the two. Polyurethane foams synthesized from castor oil phosphate flame-retarded polyol showed higher flame retardancy than that synthesized from GCO. The EG, in addition to the castor oil phosphate, provided excellent flame retardancy. This castor oil phosphate flame-retarded polyol with diethyl phosphate as plasticizer avoided foam destroy by EG, thus improving the mechanical properties. The flame retardancy determined with two different flame-retarded systems COFPL/EG and EG/COFPL/TEP flame-retarded systems revealed increased flame retardancy in polyurethane foams, indicating EG/COFPL or EG/COFPL/TEP systems have a synergistic effect as a common flame retardant in castor oil-based PUFs. This EG/COFPL PUF exhibited a large reduction of peak of heat release rate (PHRR) compared to EG/GCO PUF. The SEM results showed that the incorporation of COFPL and EG allowed the formation of a cohesive and dense char layer, which inhibited the transfer of heat and combustible gas and thus increased the thermal stability of PUF. The enhancement in flame retardancy will expand the application range of COFPL-based polyurethane foam materials.     

Renewable epoxidized cardanol‐based acrylate as a reactive diluent for UV‐curable resins

A novel kind of biobased monomer, epoxidized cardanol‐based acrylate (ECA), was successfully synthesized from cardanol via acrylation and epoxidization. The chemical structure was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Then, the ECA was employed to produce UV‐curable films and coatings copolymerized with castor oil‐based polyurethane acrylate. Compared to coatings from petroleum‐based diluent hydroxyethyl acrylate‐based castor oil‐based polyurethane acrylate resins, ECA‐based biomaterials exhibited a little inferior dilution ability but overcome the drawback of high volumetric shrinkage with a special lower value. Moreover, ultimate properties of the UV‐cured biomaterials such as thermal, mechanical, coating, swelling, and hydrophobic properties were investigated. The UV‐curing behavior was investigated using real‐time IR, and the overall double bond conversion was more than 90%. This biobased UV‐curable cardanol‐based diluent shows a promise in “green + green” materials technologies.     

Preparation of body-temperature-triggered shape-memory polyurethane with biocompatibility using isosorbide and castor oil

Shape memory polyurethanes (SMPUs) have attracted much attention in the biomedical field because they can easily control the transition temperature (T_trans) to shape memory and are biocompatible. In this study, a shape memory polyurethane with both biocompatibility and a T_trans close to the body temperature was synthesized by using natural derivatives of isosorbide and castor oil in place of petroleum-based materials. Isosorbide and castor oil were used to form net points, and polycaprolactone diol (PCL diol) acted as the switching segment. The synthesized four polyurethane (PCL diol/isosorbide/castor oil, PICU-1, 2, 3, 4) with different isosorbide contents exhibited desired thermal and mechanical properties. In the thermo-cyclic shape memory testing experiment, the PICU series demonstrated good shape memory property, with more than 95% shape recovery ratio (R_r) and more than 90% shape fixity ratio (R_f), and PICU-3 recovered its shape within 20 s in a 37 °C water bath. In addition, the PICU series proved to be safe materials with excellent biocompatibility, as indicated by the observed C2C12 cells viability and proliferation. The stent made with the PICU-3 film showed near complete magnetization at 37 °C within 18 s and proved to be a suitable self-expanding stent.     

Development of biobased polyurethane‐imides from maleinized cottonseed oil and castor oil

An eco‐friendly coating system, which is largely biobased, has been developed from castor and cottonseed oil. Cottonseed oil was functionalized with maleic anhydride by “ene” reaction to give maleinized cottonseed oil (MACSO); the anhydride groups were reacted with isocyanates to yield –NCO terminated polyurethane prepolymer. The prepolymer was further chain extended with hydroxyl groups of castor oil to give polyurethane‐imides (PUIs). The cross‐linked films thus obtained had good mechanical properties, and the imide groups in the backbone improved the corrosion resistance of PUIs as revealed by potentiodynamic polarization study. With increasing content of MACSO, thermal stability, glass transition temperatures (T_g), tensile strength, and corrosion resistance of resulting PUIs significantly increased.     

Kinetics of the Production of Castor Oil Maleate through the Autocatalyzed Thermal Reaction and the Free Radical Reaction

Castor oil maleate is used in drying oils, water‐soluble paints, healthcare products, synthetic lubricants, and as a monomer in several polymers. This maleate can be produced by a direct autocatalyzed reaction between castor oil and maleic anhydride. However, the reaction rate can be increased using a free radical catalyst. In this work, the influence of the concentration of benzoyl peroxide (BPO) and temperature in the kinetics and productivity of castor oil maleate was studied. The optimal operating condition was found at 120°C, 1 mol of maleic anhydride/mol of castor oil, and 0.003 mol of BPO/mol of castor oil, yielding 90.0% of castor oil maleate in 90 min. A kinetic model was developed, and the model parameters were estimated both for the thermal autocatalyzed reaction and the free radical reaction.     

蓖麻油及其衍生物在聚氨酯中的应用研究进展

蓖麻油是一种重要的可再生生物资源,在许多精细化学品以及聚合物方面有广泛的应用,介绍了蓖麻油及其衍生物在聚氨酯,互穿网络聚合物,聚氨酯弹性体,以及功能聚合物等方面的应用研究进展.指出以蓖麻油为原料改性和制备的聚合物材料不仅可以解决日趋紧缺的石油资源,加快聚合物工业的发展,而且改善了传统聚氨酯的耐热性,耐化学品性和力学性能等,拓宽了聚合物的应用领域.     

Room temperature synthesis and mechanical properties of two kinds of elastomeric interpenetrating polymer networks based on castor oil

Two kinds of interpenetrating polymer networks (IPNs) composed of two-component polyurethane (PU) and vinyl or methacrylic polymer (PV), namely, (polyether-castor oil)PU/PV IPN(I) and (polybutadiene-castor oil)PU/PV IPN(II), were synthesized at room temperature using benzoyl peroxide and N,N-dimethylaniline as redox initiator and dibutyltin dilaurate as catalyst. The former IPN was prepared by polymerization of castor oil, NCO-terminated polyether and vinyl or methacrylic monomer together and the latter IPN was obtained by polymerization of castor oil, NCO-terminated polybutadiene, NCO-terminated castor oil and vinyl or methacrylic monomer together. Various synthesis conditions affecting mechanical properties of the two kinds of IPNs were studied. Acrylonitrile (AN) is a good monomer for synthesizing IPN(I), but is a poor monomer for preparing IPN(II). At optimum conditions for the synthesis, both the (polyether-castor oil)PU/PAN IPNs and the (polybutadiene-castor oil)PU/polystyrene (PSt) IPNs possess permanent set about 10%, tensile strength over 13 and 11 MPa and ultimate elongation over 240% and 270%, respectively, thus behaving as elastomers. TEM micrograph of a (polybutadiene-castor oil)PU/PSt IPN showed a microphase separation in the IPN.     

Glass transition and thermal degradation of rigid polyurethane foams derived from castor oil–molasses polyols

Rigid polyurethane (PU) foams having saccharide and castor oil structures in the molecular chain were prepared by reaction between reactive alcoholic hydroxyl group and isocyanate. The apparent density of PU foams was in a range from 0.05 to 0.15 g cm^?3. Thermal properties of the above polyurethane foams were studied by differential scanning calorimetry, thermogravimetry and thermal conductivity measurement. Glass transitions were observed in two steps. The low-temperature side glass transition was observed at around 220 K, regardless of castor oil content. This transition is attributed to the molecular motion of alkyl chain groups of castor oil. The high-temperature side glass transition observed in the temperature range from 350 to 390 K depends on the amount of molasses polyol content. The high-temperature side glass transition is attributed to the molecular motion of saccharides, such as sucrose, glucose, fructose as well as isocyanate phenyl rings, which act as rigid components. Thermal decomposition was observed in two steps at 570 and 620–670 K. Thermal conductivity was observed at around 0.032 J sec^?1 m^?1 K^?1. Compression strength and modulus of PU foams were obtained by mechanical test. It was confirmed that the thermal and mechanical properties of PU foams could be controlled by changing the mixing ratio of castor oil and molasses for suitable practical applications.     

Thermal stability of segmented polyurethanes

The thermal stabilities of two series of segmented polyurethane fibres have been compared with their chemical structure. The polyurethanes were synthesized from trimethylene diamine; 4, 4′ diphenylmethane di-isocyanate and two polyether based macrodi-isocyanates. Thermal stability was measured by thermogravimetric analysis and differential thermal analysis. By comparing the changes in weight loss and DTA peaks with chemical structure it has been found possible to separate soft segment from hard segment degradation.In the initial stages stability increases as soft segment concentration increases while the reverse is true in the later stages of degradation. The 100% soft segment polymer (polytetrahydrofuran) and the 100% hard segment polymer appear to behave anomalously. It is suggested that the hard segment has a stabilizing influence on the degradation of the soft segment. The results are discussed in the light of various theories of polyurethane degradation.     

生物医用蓖麻油基聚氨酯及其接枝改性的研究进展

蓖麻油是价格低廉的可再生资源,含有大量的羟基,可代替聚酯(醚),合成出蓖麻油基聚氨酯,在生物医学领域有着广阔的发展空间。本文阐述了聚氨酯合成方法,分析了结构特性,并对其蓖麻油基聚氨酯接枝改性进行了较详细的探讨。报道了蓖麻油基聚氨酯接枝改性后的生物医用发展趋势。随着组织修复材料的发展,以天然生物质为原料而制备的该种复合生物材料是有广阔的发展前景。     

INTERPENETRATING POLYMER NETWORKS BASED ON OIL MODIFIED CASTOR OIL URETHANE AND POLY(METHYL METHACRYLATE)

Castor oil was initially subjected to an interesterification reaction with linseed and tung oils and the resulting intermediate was used for the preparation of polyurethanes and their IPNs with poly(methyl methacrylate). They were characterized for their physico-mechanical, swelling, and thermal properties. The morphologies of IPNs were studied with the aid of scanning electron microscopy and differential scanning calorimetry. On comparing the mechanical properties of castor oil polyurethane (CU) and their IPNs (C-IPNs) with those of the castor oil modified with linseed and tung oil (L-IPN and T-IPN, respectively) it was found that L-IPNs showed higher tensile strength, hardness, and better compatibility than C-IPNs. All IPNs showed synergistic effect in elongation and exhibited similar thermal behavior with no significant change with respect to their composition. However, the castor oil polyurethane and their IPNs showed relatively higher elongation and better resistance to solvents.     

用可再生原料合成聚氨酯脲水分散液——成膜后的结构与性能研究

以不同组成的蓖麻油和二官能度聚醚多元醇 (GE 2 10 )等原料合成了聚氨酯脲 (PUU)水分散液 ,研究了蓖麻油 GE 2 10的组成对PUU膜结构与性能的影响 .结果表明 ,由GE 2 10合成的PUU虽软硬段间存在一定的相容性 ,但其中脲羰基的氢键化程度高 ,硬段形成较好的有序结构 ,导致PUU膜具有较高的拉伸强度及断裂伸长率 ,但弹性模量和硬度下降 .在蓖麻油合成的PUU中脲羰基的氢键化程度及硬段有序结构均受到化学交联结构的抑制 ,故PUU膜的拉伸强度和断裂伸长率降低 ,但弹性模量及硬度较高 .由蓖麻油与GE 2 10在一定的组成范围内合成的PUU膜 ,具有优良的综合平衡的力学性能 ,后者与材料的结构形态相符     

酚氧树脂／蓖麻油交联聚氨酯

使2.2-(4’-羟基苯基)丙烷(双酚A)与环氧氯丙烷反应制得了带端羟基的酚氧树脂(HBA),将其与蓖麻油共混,用2.4-甲苯二异氰酸酯(TDI)作固化剂,制得了一系列交联聚氨酯。DSC和DMA测试结果表明,这种聚氨酯只有一个T_g。改变NCO/OH摩尔比及HBA/(HBA 蓖麻油)比可制得具有较好阻尼性能的聚氨酯材料。     

New potentially environmentally friendly copolymer of styrene and maleic acid—castor oil monoester

The maleic acid‐castor oil monoester (MACO) was synthesized and was used as monomer to synthesize a new potentially environmentally friendly copolymer of styrene and MACO (poly‐St/MACO) by suspension polymerization. Under the appropriate conditions, the poly‐St/MACO with yield of 81%, number average molecular weight of 44100 g/mol, and molecular weight distribution of 1.5 could be obtained. The chemical structures of the MACO and resulting copolymer were confirmed by Mass Spectrometry Infrared Spectroscopy and Nuclear Magnetic Resonance Spectroscopy H[1]. The results of thermogravimetric analysis and biodegradation test showed the poly‐St/MACO can be used as a new potentially environmentally friendly material with excellent thermal stability. Copyright © 2011 John Wiley & Sons, Ltd.     

Hydrophobic modification of cellulose nanocrystal via covalently grafting of castor oil

Hydrophobic cellulose nanocrystals (CNs) have been prepared by grafting isocyanate-terminated castor oil, a kind of natural vegetable oil, onto their surface. The existence of castor oil component in the modified cellulose nanocrystals was verified by Fourier transform infrared spectroscopy, solid-state ¹³C NMR spectra and X-ray photoelectron spectroscopy. At the same time, X-ray diffraction and transmission electron micrographs further proved that the crystalline structure and large aspect ratio of cellulose nanocrystals were essentially preserved after chemical grafting. Furthermore, the surface of modified cellulose nanocrystals appeared to be hydrophobic as indicated by contact angle measurements. The value of the polar component of surface energy decreased from 21.5 mJ/m² to almost zero via grafting castor oil. These novel hydrophobic castor oil-grafted cellulose nanocrystals appear as valuable alternatives to formulate bionanocomposites with non-polar polymers for optimized performances.     

PHYSICO-MECHANICAL,OPTICAL, AND WAXS STUDIES ON CHAIN EXTENDED POLYURETHANE

Thermoset polyurethane (PU) elastomers were prepared using castor oil, 4,4′-methylenebis(phenyl isocyanate) (MDI), and tol-uene-2,4-diisocyanate (TDI). The effect of aromatic diamines on the physico-mechanical and optical properties of chain extended polyurethane prepared using castor oil has been investigated. Tensile strength and percent elongation lies in the range 13–24 MPa and 76–32, respectively. Higher tensile strength was observed for 4,4′-diaminodiphenylsulphone (DDS) than the 4,4′-diaminodiphenylmethane (DDM) chain extender. The properties imparted by the extenders are explained on the basis of the groups present in the diamines. These changes have been interpreted quantitatively in terms of microcrystalline parameters computed using wide-angle X-ray scattering data.     

Development of Green Waterborne UV-Curable Castor Oil-Based Urethane Acrylate Coatings: Preparation and Property Analysis

A series of novel waterborne UV-curable polyurethane dispersions were synthesized from castor oil, IPDI, DMPA, and HEMA by the acetone process. The prepared UV-PUD was mixed with three different monomers and characterized for the parameters relevant to the study by physical, spectroscopic, and chemical methods. The effect of monomer type on the physicochemical and thermal properties of UV-PUDs revealed that the number of unsaturated groups present in the monomer had a pronounced effect on physicochemical, mechanical, and thermal properties. The combination of renewable resource and environmentally compliant technology give these UV-PUDs potential scope in coating applications.     

毛竹屑与玉米淀粉共液化产物制备聚氨酯泡沫研究

采用单因素试验设计,研究了液化剂组成、液比以及毛竹屑与淀粉的比例对液化产物理化性质、及所制备的聚氨酯泡沫材料的物理力学指标影响.结果显示当以50%乙二醇+50%碳酸亚乙酯混合物作为液化剂、添加相当于液化剂质量3%的浓硫酸为催化剂、在(150±5)℃(油浴)和常压条件下,液化150min,搅拌速度30r/min,取得本试验条件下最好的竹屑液化效果,液化产物中竹屑含量25%,残渣率3.96%,但该液化产物中天然聚合物碎片含量少,所制备的聚氨酯泡沫材料塌陷;竹屑与玉米淀粉共液化有效提高了液化产物中生物质的含量,但占液化剂质量25%竹屑+占液化剂质量125%玉米淀粉共液化产物粘度太高(8.85Pa.s);而20%竹屑+130%玉米淀粉的共液化产物与4,4′-二苯基甲烷二异氰酸酯以及各种助剂按异氰酸酯基/羟基摩尔比为1.1配合时,所制备的聚氨酯泡沫材料表观密度为33.6kg/m3、压缩强度118kPa、弹性模量6.91MPa,在周年生物降解试验中,该生物质基聚氨酯硬质泡沫失重率为12.63%.