苯乙烯-马来酸酐共聚物脂肪醇单酯钠盐的制备及其表面活性

以苯乙烯-马来酸酐共聚物(SMA)和高级脂肪醇为原料制备了一系列SMA脂肪醇单酯钠盐。并用核磁共振仪和凝胶渗透色谱仪对接枝产物进行了表征,测定了酯化前后酸值的变化,研究了酯化物钠盐的水溶性及其表面活性。结果表明,脂肪醇的转化率均在85%以上,其中SMA-g-C12钠盐的水溶性较好;25℃时,SMA-g-C12钠盐的表面活性最好,其临界胶束浓度(cmc)为0.94 g.L-1,γcmc为25.04 mN.m-1。     

MBS接枝共聚物对PMMA树脂的增韧研究

采用乳液聚合法在聚丁二烯（PB）乳胶粒子上接枝苯乙烯（St）和甲基丙烯酸甲酯(MMA),合成了一系列的MBS接枝共聚物（简称MBS）,将其与聚甲基丙烯酸甲酯（PMMA）进行熔融共混制备PMMA/MBS共混物,研究了PB及相对分子质量调节剂叔十二烷基硫醇（TDDM）含量对共混物力学性能和微观形态结构的影响。结果表明,随着MBS中PB所占比例的增加,共混物的冲击强度表现出先增大后减小的趋势,当PB所占比例为50 %（质量分数,下同）时,共混物的冲击强度达到200 J/m,而拉伸强度表现出上升的趋势;随着TDDM用量的增加,MBS的接枝率和接枝效率降低,导致共混物的冲击强度先增加后减小;随着MBS中PB所占比例的增加,接枝率的逐渐降低,MBS在PMMA基体中分散程度逐渐变差。     

聚乳酸水蒸气阻隔性的改性

聚乳酸(PLA)用于产品包装时不仅要满足所必需的力学性能、化学稳定性、透明性、印刷性以及热封性等,还要满足产品对阻隔性的要求.采用共混、添加助剂的方法以提高PLA对水蒸气的阻隔作用.结果显示:乙烯-乙烯醇共聚物(EVOH)、有机蒙脱土(OMMT)的加入可以降低PLA的水蒸气透过率(WVTR),且随着其含量的增加,WVTR值逐渐减小,当EVOH质量含量达到50％时,WVTR值减小了61％,OMMT含量达到9％时,WVTR值减小了58％;在OMMT/PLA共混物中加入聚癸二酸丙三醇酯(PGS)后,WVTR值增加.     

ANA-MA-MAC三元阻垢剂的合成及性能研究

以乌头酸(ANA)、马来酸(MA)和丙烯酸甲酯(MAC)为单体原料,(NH4)2S2O8为引发剂,在异丙醇为链转移剂作用下,采用水溶液聚合法合成了ANA-MA-MAC三元聚合物阻垢剂。研究该聚合物对碳酸钙垢的阻垢性能。结果表明,ANA-MA-MAC的质量浓度为10.0 mg/L,水的硬度为6.0 mg/mL,在弱碱性,阻垢率可达97%。     

Synthesis of a novel intumescent flame retardant and its application in EVM

A novel phosphorous-nitrogen structure containing intumescent flame retardant, 4,4-diaminodiphenyl methane bi(2,2-dimethyl-1,3-propanediol) phosphoramidate (DBDPP) was synthesized and characterized. Thermal stability and flammability properties of ethylene vinyl-acetate copolymer rubber(EVM)/DBDPP composites were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI) test and UL-94 measurement, respectively. The results showed that the addition of DBDPP enhanced the thermal stability and flame retardancy of EVM significantly. The weight of residues improved greatly with the addition of DBDPP. SEM investigations revealed that a strong charred layer was formed from EVM/DBDPP composites during combustion. It is confirmed that the char structure was a critical factor for flame retardancy of EVM rubber. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Solid state NMR analysis of poly(L‐lactide) random copolymer with poly(ε‐caprolactone) and its reactive extrusion process

A random copolymer based on poly(L ‐lactide) (PLA) with poly(ε‐caprolactone) (PCL) was prepared and characterized by mechanical testing and solid state NMR, compared with a polymer blend. For a monofilament sample consisting of PLA/PCL random copolymer, there were negative correlations between the CL content and the mechanical properties: tensile strength, tensile elastic modulus, flexural rigidity, and flexural hysteresis decreased with increasing CL content. In contrast, the mechanical properties of the polymer blend were only slightly changed by addition of the CL unit. For the random copolymer, the addition of a small amount of CL reduced relaxation times, T₁C and T_1ρH, gradually. The T₁C and T_1ρH values correlated closely with the tensile elastic modulus and the tensile strength, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Working mechanism of a high temperature (200°C) synthetic cement retarder and its interaction with an AMPS®‐based fluid loss polymer in oil well cement

A copolymer comprising of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS®) and itaconic acid (molar ratio 1 : 0.32) was synthesized by aqueous free radical polymerization and probed as high temperature retarder for oil well cement. Characteristic properties of the copolymer including molar masses (M_w and M_n), polydispersity index and anionic charge amount were determined. The copolymer possesses a M_w of ～ 2 × 10⁵ g/mol and is highly anionic. HT/HP consistometer tests confirmed effectiveness of the retarder at temperatures up to 200°C. The working mechanism of NaAMPS®‐co‐itaconic acid was found to rely exclusively on its huge calcium binding capacity (5 g calcium/g copolymer). It reduces the amount of freely dissolved, nonbound calcium ions present in cement pore solution and thus hinders the growth of cement hydrates because of lack of calcium. The value for the calcium binding capability is 46 times higher than the stoichiometric amount per ? COO^? functionality. Consequently, calcium also coordinates to other donor atoms present in the retarder. NaAMPS®‐co‐itaconic acid also adsorbs onto cement, as was evidenced by TOC analysis of cement filtrates, zeta potential measurement and decreased rheology of cement pastes. However, adsorption plays no role in the retarding mechanism of this copolymer. Combination of NaAMPS®‐co‐itaconic acid retarder with a common CaAMPS®‐co‐NNDMA fluid loss additive (FLA) revealed that competitive adsorption on cement between these two admixtures occurs. The retarder fills interstitial adsorption sites on cement located between those occupied by the larger FLA molecules. In consequence, fewer amounts of CaAMPS®‐co‐NNDMA can adsorb and its effectiveness is reduced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Correlation of miscibility and mechanical properties of polypropylene/olefin block copolymers: Effect of chain composition

This study examines the miscibility and mechanical properties of isotactic polypropylene (iPP) and olefin block copolymer (OBC) blends (70/30 wt %). The blends exhibit phase-separated morphology. The OBC domain size decreases with increasing the 1-octene content in the soft segment. The crystallization, melting behavior, and the long spacing of the iPP component in the blends are nearly the same as those of neat iPP, while the T_g of the iPP component shifts slightly to lower temperature. “Blocky” OBC is immiscible with iPP, while the soft segment rich polymers in OBC could be partially miscible with iPP. The impact strength of the blends is greatly increased with increasing the 1-octene content in the OBC soft segment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Copolymers of Phenoxyethyl Methacrylate with Butyl Methacrylate: Synthesis,Characterization and Reactivity Ratios

Phenoxyethyl methacrylate (POEMA) and butyl methacrylate (BMA) were copolymerized by free-radical copolymerization using α,α′-azobisisobutyronitrile (AIBN) in 2-butanone solution at 333±1 K. Copolymers were characterized by FTIR, ¹H-NMR and ¹³C-NMR spectroscopic methods and by comparison of the spectra with the corresponding homopolymers. Thermogravimetric analysis of the copolymers was carried out in order to know their thermal stability. Copolymer composition was established by ¹H-NMR analysis. Monomer reactivity ratios (MRR) were computed using the classical Fineman – Ross (FR) and Kelen – Tüdos (KT) procedures. MRR were also estimated using a nonlinear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The mean sequence lengths of the copolymers were estimated and suggest that random copolymers were obtained.     

Development and Applications of Novel Acrylic Copolymers

The monomer 2,4-dichlorophenylacrylate was synthesized from 2,4-dichlorophenol and characterized by conventional methods. Homo- and copolymers of 2,4-dichlorophenylacrylate and butylmethacrylate were synthesized with different feed ratios using N,N-dimethylformamide as a solvent and 2,2′-azobisisobutyronitrile (AIBN) as an initiator at 70°C. The resulting polymers were characterized by infrared spectroscopy. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. The monomer reactivity ratios were determined by applying the conventional linearization method of Fineman-Ross and Kelen-Tudos. The reactivity ratios values of 2,4-dichlorophenylacrylate and butylmethacrylate obtained from F-R plot are 0.91 and 1.15 respectively and from K-T plot, 0.97 and 1.24 respectively. The molecular weight and polydispersity of copolymers were determined by gel permeation chromatography (GPC). Thermo gravimetric analyses of the polymers were carried out in a nitrogen atmosphere. Thermal data suggest that the polymers underwent double decomposition. Homo and copolymers were tested for their antimicrobial properties against various microorganisms and showed strong inhibitory effects.