Effect of MAPP and TMPTA as compatibilizer on the mechanical properties of cellulose and oil palm fiber empty fruit bunch–polypropylene biocomposites

The effect of compatibilizers, namely, maleic anhydride grafted polypropylene (MAPP GR-205) and trimethylolpropane triacrylate (TMPTA), on the mechanical and morphological properties of the PP-cellulose (derived from oil palm empty fruit bunch fiber) and PP-oil palm empty fruit bunch fiber (EFBF) biocomposites has been studied. The ratio of PP : cellulose and PP : EFBF is fixed to 70 : 30 (wt/wt%) while the concentration of the compatibilizer is varied from 2.0 to 7.0 wt%. Results reveal that at 2.0 wt% of MAPP concentration, tensile strength of PP-EFBF biocomposite is significantly improved. This is due to the enhanced EFBF matrix adhesion resulting in an improvement in EFBF biocomposite performance. There are no significant changes observed in the PP-cellulose biocomposite properties upon the addition of MAPP. In contrast to the tensile strength, flexural modulus and impact strength are significantly improved with the addition of 2.0 wt% TMPTA to PP-cellulose biocomposite. The enhancement of mechanical properties in the presence of TMPTA is believed to be attributed to crosslinking of multifunctional monomer with the hydroxyl groups of cellulose.     

含三个硬脂酰胺基的树枝状季铵盐的制备

由三羟甲基丙烷三丙烯酸酯(TMPTA)和乙二胺(EDA)直接进行M ichael加成反应,合成端基为3个NH2的树枝状大分子G(NH2)3,用硬脂酰氯将其端氨基进行酰胺化得到端基为3个硬脂酰基的树枝状大分子GS(R)3,产率为82.4%。GS(R)3进一步与碘甲烷反应,其分子中的3个仲氨基被季铵化,生成树枝状季铵盐GI(R)3,产率为82.0%。讨论了反应温度、反应时间和原料配比对GS(R)3和GI(R)3产率的影响,并用红外、核磁和元素分析对GS(R)3和GI(R)3的结构进行表征。     

多官能单体TMPTA在LDPE表面光接枝聚合研究

以二苯甲酮(BP)为光引发剂、丙酮和水的混合物为溶剂,研究了室温下多官能单体三羟甲基丙烷三丙烯酸酯(TMPTA)在低密度聚乙烯(LDPE)表面的光接枝聚合(λ>300nm).研究表明,多官能单体的接枝速率较快,接枝聚合易产生交联结构,聚合后仍残留双键;延长聚合反应时间、增加单体用量有利于单体接枝转化率的提高;随引发剂用量增加,单体接枝转化率出现一峰值;在研究范围内,混合溶剂中水含量增加可使单体接枝转化率明显提高.扫描电镜观察到接枝膜表面形成了许多小球,表面粗糙度增加,疏水性提高.     

Characterization of electron-beam-modified surface coated clay fillers and their influence on physical properties of rubbers

A novel process of surface modification of clay filler has been developed by coating this with an acrylate monomer, trimethylol propane triacrylate (TMPTA) or a silane coupling agent, triethoxy vinyl silane (TEVS) followed by electron beam irradiation. Characterization of these surface modified fillers has been carried out by Fourier-transform infrared analysis (FTIR), electron spectroscopy for chemical analysis (ESCA), wettability by dynamic wicking method measuring the rise of a liquid through a filler-packed capillary tube and water flotation test, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Presence of the acrylate and the silane coupling agent on the modified fillers has been confirmed from FTIR, ESCA, and EDX studies, which has also been supported by TGA studies. The contact angle measurement by dynamic wicking method suggests improvement in hydrophobicity of the treated fillers, which is supported by water flotation test especially in the case of silanized clay. However, XRD studies demonstrate that the entire modification process does not affect the bulk properties of the fillers. Finally, both unmodified and modified clay fillers have been incorporated in styrene butadiene rubber (SBR) and nitrile rubber (NBR). Rheometric and mechanical properties reveal that there is a definite improvement using these modified fillers specially in the case of silanized clay compared to the control sample, probably due to successful enhancement in interaction between the treated clay and the base polymer.     

Precipitation Polymerization in Ethanol and Ethanol/Water to Prepare Uniform Microspheres of Poly(TMPTA‐styrene)

The precipitation polymerization of styrene‐trihydroxymethyl propane triacrylate has been carried out using ethanol and an ethanol/water mixture as the solvent. Uniform microspheres with high monomer conversion are achieved within 4 h, a much shorter polymerization time than that reported for the precipitation polymerization of divinyl benzene‐styrene in acetonitrile. The results clearly demonstrate that use of water as a co‐solvent is indeed very effective to promote the polymerization to high conversion and to obtain uniform microspheres. With no water under the otherwise same experimental conditions, only about 57% of monomer conversion is obtained; while the monomer conversion is remarkably increased to 96% when 12 vol.‐% of water is used.

     

Thermal analysis of hydrolysis and degradation of biodegradable polymer and bio-composites

The purpose of this study was to conduct a thermal analysis of the hydrolysis and degradation behavior of biodegradable polymers and bio-composites at 50°C and 90% relative humidity (RH). With increasing hydrolysis time, the thermal stability and degradation temperature of polybutylene succinate (PBS) slightly decreased. The glass transition temperature (T _g) and melting temperature (T _m) of PBS and the anti-hydrolysis agent treated PBS did not vary significantly with increasing hydrolysis time, whereas those of the trimethylolpropane triacrylate (TMPTA)-treated PBS slightly increased. With increasing hydrolysis time, the storage modulus (E’) values of the bio-composites decreased, whereas those of the TMPTA treated bio-composites slightly increased. Also, the tan values of the anti-hydrolysis agent and TMPTA treated PBS-BF bio-composites were slightly lower than those of the non-treated bio-composites, due to the reduction in their degree of hydrolysis. The tanδ_max peak temperature (T _g) of the anti-hydrolysis agent treated bio-composites was not significantly changed, whereas that of the TMPTA treated bio-composites was increased.     

树枝状多氨基大分子环氧树脂固化剂的研究

三羟甲基丙烷三丙烯酸酯（TMPTA）和乙二胺（EDA）进行Michael加成反应，合成了外围带多个活泼氢原子的树枝状大分子G1.0（NH2）。最佳合成条件为：n(EDA)=1:12,甲醇作催化剂，50℃反应24h,产率97.01%,G1.0(NH2)的质量分数为96.02%用IR、NMR和元素分析表征G1.0（NH2）的结构。与EDA/环氧树脂体系相比，G1.0（NH2）/环氧树脂体系适用期较长、凝胶时间和快速度固化。G1.0（NH2）在固化过程中分两阶段逐渐放热，且总放热量小于EDA固化剂体系，TGA分析表明两种体系固化产物热稳定性相似。     

Phase-mixed poly(ethylene glycol)/poly(trimethylolpropane triacrylate) semi-interpenetrating polymer networks obtained by rapid network formation

Semi-interpenetrating polymer networks (semi-IPNs) of poly(ethylene glycol) (PEG) in poly(trimethylolpropane triacrylate) (TMPTA) were synthesized from PEG melts in neat TMPTA monomer, using PEG of molecular weights from 4000 to 100,000 g/mol. Differential scanning calorimetry and transmission electron microscopy were used to examine phase separation occurring during network formation. The degree of phase separation was observed to depend upon the rate of PEG aggregation relative to the rate of network formation during TMPTA polymerization. Higher molecular weight PEG and acrylate-functionalized PEG formed more phase-mixed networks compared to lower molecular weight PEG; acetatefunctionalized PEG showed no difference from unmodified PEG in the extent of phase mixing. For networks that demonstrated phase separation, the PEG was observed to be in two states: some being phase mixed and solvent inextractable, and some being phase separated and solvent extractable. Phase-mixed networks could be obtained from this thermodynamically incompatible polymer pair utilizing rapid photopolymerization systems to overcome PEG phase aggregation and kinetically entrap the PEG in a nonequilibrium phase-mixed state. These mixed-phase semi-IPNs of PEG and TMPTA may be useful in biological applications where the presence of PEG is desired throughout the bulk matrix rather than as a surface graft to reduce biological interactions. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of novel ionophores of double-armed penta-crown ethers

Unique structures of novel ionophores of double-armed penta-crown ethers were successfully synthesized. Diaza 18-crown-6 was designed as the parent crown ring. The penta-crown ethers were prepared by the reaction of trimethylolpropane triacrylate (TMPTA) with diaza 18-crown-6 and further with 1-aza crown ethers through the Michael reaction. The newly synthesized penta-crown ethers were characterized by ¹H NMR, ¹³C NMR, FAB mass spectrum, IR and elemental analyses, respectively.     

低密度三羟甲基丙烷三丙烯酸酯泡沫的研制

 以三羟甲基丙烷三丙烯酸酯（TMPTA）为原料,结合紫外光固化及冷冻干燥工艺,成功制备了密度在4～20 mg/cm³、可自支撑的TMPTA泡沫柱。试验研究发现,泡沫的收缩导致实际密度与理论密度的比值大于1,且随理论密度的增加而减小;热失重测试表明泡沫的热分解温度达到290 ℃;SEM测量表明泡沫具有均匀、开放的网络结构。压汞仪测试表明泡沫的孔径主要分布在3.0～7.5 mm之间,平均孔径为7.37 mm。TMPTA泡沫柱已成功地应用于近年的Z箍缩物理试验中。