Preparation and physical properties of rubber-modified epoxy resin using poly(urethane acrylate)/poly(glycidyl methacrylate-co-acrylonitrile) core-shell composite particles

Poly(urethane acrylate)/poly(glycidyl methacrylate-co-acrylonitrile) core-shell composite particles were prepared using two-stage emulsion polymerization. Composite particle sizes were varied from 48 to 200 nm by introducing polyoxyethylene groups into the urethane acrylate molecules. The morphology of the two-stage composite latex was inferred using surface energy measurements and titration of the emulsion. In the two-stage latex, which was prepared using relatively small core particles (about 40 nm), an inverted core-shell morphology was obtained. It was believed that the high polarity of the core surface and the low stage ratio of core to shell made the core-shell morphology more unstable thermodynamically. When the core of the two-stage latex was more crosslinked, the morphology was perfectly prevented from inverting because a higher kinetic barrier between the core-shell and inverted core-shell structures was achieved. The impact strength of the modified epoxy resin increased with the decrease of composite particle sizes and the increase of the shell thickness. In particular, when the average size of the composite particle was 50 nm and the stage ratio was 70/30, the impact strength of the modified epoxy resin increased more than 20 times compared to that of pure epoxy resin. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1589–1600, 1997     

聚乳酸-壳聚糖共聚物载药微球的制备及性能研究

为了改善聚乳酸(PLLA)的组织相容性及细胞亲和性,提高盐酸乌拉地尔生物利用率,文中在催化剂4-(二甲胺基)吡啶与N,N'-二环己基碳酰亚胺共同作用下,将含亲水基团的碱性聚电解质壳聚糖(CS)与PLLA共聚,制备了聚乳酸-壳聚糖接枝共聚物(PLCS),采用溶剂挥发法制备盐酸乌拉地尔PLCS微球并对其结构进行了表征,同时对微球的包封率和药物释放进行了测试。通过有机相加入乙醇的方法可以提高微球对药物的包封率。结果表明,当无水乙醇与三氯甲烷的体积比为1∶2时,制得的微球包封率最高,达到34.86%。体外药物释放结果表明,PLCS微球具有明显的缓释作用,其释药动力学满足Higuchi方程。     

Configurational statistics of poly(L-lactide) and poly(DL-lactide) chains

Conformational characteristics of poly(lactide)s have been investigated by density functional theory and ab initio molecular orbital (MO) calculations and NMR experiments on model compounds. Characteristic ratios, configurational entropies, and internal energies of poly(L-lactide) and poly(DL-lactide), whose stereosequences were generated by Bernoulli and Markov stochastic processes, were calculated under the refined rotational isomeric state scheme with conformational energies and geometrical parameters derived from the MO calculations. In terms of the conformational characteristics thus revealed, we have elucidated the reason why unperturbed chain dimensions determined experimentally for poly(L-lactide) are scattered considerably and, furthermore, discussed crystallization and crystal structures of poly(L-lactide) and molecular characteristics of poly(DL-lactide) synthesized from rac-lactide with stereospecific polymerization catalysts.     

Preparation of poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/epoxy laminate with functionalized PPE resin

Thermal expansion property at 288°C and methylene chloride resistance of poly(2,6-dimethyl-1,4-phenylene ether (PPE)/epoxy laminate were found to be affected by the functionality on PPE resin. Nonlofting PPE/epoxy laminates were prepared with the PPE grafted with fumaric acid or the PPE having (di-n-butylamino) methyl substituent on the polymer backbone. Employing vacuum-vented PPE extrudate or phenol-redistributed PPE was also effective in improving the PPE/epoxy laminate properties. Attempts to preparing a real PPE/epoxy interpenetrating network as the matrix material for the laminate were also made by incorporating both PPE crosslinker and epoxy curing catalysts in the same formulation. © 1993 John Wiley & Sons, Inc.     

Phase separation of poly(ether sulfone imide) modified epoxy resin

Poly(ether sulfone imide)s (PEI) with molecular weight M_n ∼ 10⁴ were synthesized from 3,3′,4,4′-benzophenone tetracarboxylic dianhydride and amine terminated poly(ether sulfone) having molecular weights ranging from M_n ∼ 400 to M_n ∼ 4000. Thus, the PEIs had the same molecular weight but various imide and ether sulfone contents. The PEIs were mixed with a stoichiometric mixture of diglycidyl ether bis-phenol-A (DGEBA)/diamino diphenyl sulfone (DDS). The effect of PEI on the curing reaction of DGEBA/DDS and the morphology of the polymer blend were studied by differential scanning calorimetry (DSC) and optical microscopy. In the DGEBA/DDS/PEI blend with a fixed PEI molecular weight and PEI concentration but with various imide content, the experimental data revealed the PEI with a higher content of ether sulfone had a lower T_g and a better compatibility with solvents and epoxy resins; the curing reaction rate of DGEBA/DDS/PEI was faster for PEI with a higher imide content; the DSC data of cured DGEBA/DDS/PEI showed two T_gs, indicating phase separation between PEI and cured epoxy resins; and the data of optical microscopy showed that the compatibility of PEI with epoxy resins increased with the content of ether sulfone in PEI. © 1996 John Wiley & Sons, Inc.     

New thermosetting resin from poly(p‐vinylphenol) based benzoxazine and epoxy resin

Poly(p‐vinylphenol) (VP) based benzoxazine was prepared from VP, formaline, and aniline. The curing behavior of the benzoxazine with the epoxy resin and the properties of the cured resin were investigated. Consequently, the curing reaction did not proceed at low temperatures, but it proceeded rapidly at higher temperatures without a curing accelerator. The reaction induction time or cure time of the molten mixture from VP based benzoxazine and epoxy resin was found to decrease, compared with those from conventional bisphenol A based benzoxazine and epoxy resin. The curing reaction rate of VP based benzoxazine and epoxy resin increased more than that of conventional bisphenol A based benzoxazine and epoxy resin. The properties of the cured resin from neat resins and from reinforced resins with fused silica were evaluated. The cured resins from VP based benzoxazine and epoxy resin showed good heat resistance, mechanical properties, electrical insulation, and water resistance compared to the cured resin from VP and epoxy resin using imidazole as the catalyst. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 555–565, 2001     

The study on poly(ether sulfone) modified cyanate ester resin and epoxy resin cocuring blends

Poly(ether sulfone) terminated with phenolic hydroxyl groups modified cyanate ester resin and epoxy resin cocuring blends were investigated by differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, rheometry, and mechanical properties measurement. The results suggested that poly (ether sulfone) (PES) could accelerate the polycyclotrimerization reaction of cyanate ester and cocuring processes between cyanate ester and epoxy of modified blends because of the presence of phenolic hydroxyl groups at the end of the PES molecules. It was found that the evolution of the morphologies and complex viscosities of the modified blends sensitive to molecular weight and content of PES, the tensile strength and elongation at break of the modified blends were correlated with the morphologies of modified blends. Moreover, the evolution of complex viscosities of the modified blends also showed an exponential growth at the early stage of phase separation, which demonstrated experimentally that the coarsening processes of droplets of bisphenol‐A dicyanate and diglycidyl ether of bisphenol A and the final morphologies obtained in the blends modified with PES were affected by viscoelastic behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

环氧基POSS改性环氧树脂的研制与性能研究

以苯基三乙氧基硅烷(PTES)和β-3,4-环氧环己基乙基三甲氧基硅烷(A186)为原料,甲醇、乙醇混合溶液为溶剂,酸性条件下水解制得含有Si—H键的环氧基低聚倍半硅氧烷(EP-POSS),通过傅里叶红外光谱(FT-IR)、核磁共振氢谱(¹H NMR)、核磁共振硅谱(²⁹Si NMR)等手段对其结构进行表征。用制备的EP-POSS对环氧树脂进行改性,分析了EP-POSS用量对树脂涂层附着力、耐冲击性、疏水性、耐热稳定性的影响。结果表明:当EP-POSS加入量为5%时,环氧树脂涂层附着力达到1级,耐冲击性达到50 cm,对水的接触角为90°,热稳定性大幅提升。     

Curing of epoxy resin with poly(m‐phenylene methylphosphonate)

The mechanism and kinetics of curing of epoxy resin with poly(m‐phenylene methylphosphonate) (PMP) was studied by extraction and swelling experiments, DSC, ³¹P NMR, and FTIR. It was shown that at linear heating of 20°C/min PMP cures bisphenol A type epoxy resin at 230–300°C, whereas in the presence of catalytic amount of 2‐methyl imidazole the curing occurs at 200–230°C. Under isothermal conditions, epoxy resin was cured with PMP after 40–70 min at 150°C. An unusual mechanism of curing due to opening and insertion of epoxy into the phosphonate bond was suggested. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4011–4022, 2006     

环氧端基酚酞聚芳醚腈改性环氧树脂胶粘剂性能的研究

通过差示扫描量热 (DSC)、热解重量分析 (TGA)和粘接强度的测定 ,对环氧端基酚酞聚芳醚腈改性的环氧树脂胶粘剂的性能进行了研究     

Preparation and characterization of electrospun poly (lactide-co-glycolide) membrane with different L-lactide and D-lactide ratios

Poly (lactide-co-glycolide) (PLGA, LA/GA = 80/20) with different L-lactide and D-lactide molar ratio (L-LA/D-LA = 1.0∼0.5) has been synthesized, and electrospun into nanofibrous membranes. The obtained copolymers were characterized by ¹HNMR, Polarimeter, GPC and DSC. The relationship between the contraction of the membranes and the L-LA/D-LA ratio of copolymers has been investigated through DSC, SEM and XRD. The results indicated that with the L-LA/D-LA ratio decreasing, the crystal fragments in copolymer decreased significantly even disappeared; meanwhile, the contraction of the membranes in PBS at 37 °C increased. The mechanism of the contraction of electrospun PLGA membrane during incubated is proposed based on the present results.     

球形聚合单宁-纤维素树脂的制备及吸附性能

单宁与多聚甲醛交联合成单宁酚醛聚合物,再以环氧氯丙烷为交联剂,将单宁酚醛聚合物与纤维素通过反相悬浮交联制备球形聚合单宁-纤维素树脂。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）对球形聚合单宁-纤维素树脂的结构进行了表征,并考察了球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附性能。结果表明,球形聚合单宁-纤维素树脂具有多孔的结构,树脂网络中含有大量的酚羟基;球形聚合单宁-纤维素树脂对盐酸小檗碱具有较好的吸附性能,当盐酸小檗碱浓度为600 mg·L^-1、吸附温度为298 K时,最大饱和吸附量可达245.92mg·g^-1;球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附过程符合Langmuir吸附等温模型和准二级吸附动力学方程,热力学研究数据表明球形单宁-纤维素树脂对盐酸小檗碱的吸附是一个自发放热的物理吸附过程。该树脂在分离提纯生物碱方面具有潜在的应用前景。     

环氧基体树脂的制备与性能表征

以MTHPA(甲基四氢苯酐)为固化剂,XY-748(C_(12-14)烷基缩水甘油醚)为稀释剂,DMP-30[2,4,6-三(二甲氨基甲基)苯酚]为促进剂,CTBN(端羧基丁腈橡胶)为增韧剂,再辅以扩链剂D-248改性混合环氧树脂F-47/E-51,制得了无溶剂新型环氧基体树脂;并对基体树脂的变温拉伸剪切强度、凝胶化时间、固含量、吸水性、介电性能、体积电阻率、接触角与表面能等进行了测试。研究结果表明:此新型环氧基体树脂具有优异的力学性、介电以及疏水性能。     

双环戊二烯邻甲酚环氧树脂的合成与表征

以邻甲酚和双环戊二烯为原料,通过Friedel-Crafts反应,合成了双环戊二烯邻甲酚酚醛树脂(DPR),该树脂用环氧氯丙烷进行环氧化制备出双环戊二烯邻甲酚环氧树脂(DER).所得环氧树脂的环氧值为0.33,结构也得到了表征.分别以甲基六氢苯酐(MeHHPA)和聚酰胺651作为固化剂,通过DSC考察了该树脂的固化,固化温度峰值分别为141℃和168℃.在双酚A环氧树脂E51中添加不同比例的所制备的双环戊二烯邻甲酚环氧树脂DER,发现固化树脂的玻璃化转变温度Tg同单纯的E51固化树脂相比提高约20℃.     

环氧树脂微胶囊的制备研究

以脲醛树脂为壁材,E-51环氧树脂为囊芯,通过原位聚合法制备了环氧树脂微胶囊。探讨了反应过程中脲醛量比及反应温度、体系pH值、搅拌速度等实验条件对微胶囊表面形貌、结构、粒径及其分布和包封率的影响。并通过多种方法对微胶囊进行了检测和表征,在此基础上提出了制备环氧树脂微胶囊的最佳反应条件:n(尿素):n(甲醛)=1:2．0,以NH4Cl为酸性催化剂,催化剂分批加入,酸化3h,终点pH为2．0,反应温度70℃,搅拌转速450r／min,固化2h。     

Isothermal crystallization and chain mobility of poly(L-lactide)

Isothermal melt crystallization of poly(L-lactide) (PLLA) has been studied in the temperature range of 90 to 135°C. A maximum in crystallization kinetic was observed around 105°C. A transition from regime II to regime III is present around 115°C. The crystal morphology is a function of the degree of undercooling. At crystallization temperatures (T_c) below 105°C, further crystallization occurs upon heating; this behavior is not detected for T_c above 110°C. The analysis of the heat capacity increment at glass transition temperature (T_g) and of dielectric properties of PLLA indicates the presence of a fraction of the amorphous phase which does not relax at the T_g, and the amount of this so-called rigid amorphous phase is a function of T_c. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 911–919, 1997     

新型脂肪族超支化环氧树脂的制备及其改性作用

采用一步法合成了新型脂肪族超支化环氧树脂HTPE-3,利用FT-IR对其结构进行了表征。研究了双酚A型环氧树脂E-51/HTPE-3杂化树脂的力学性能和热性能。结果显示,杂化树脂的韧性和强度随HTPE-3含量的增加先增加后降低,具有极大值;当HTPE-3质量分数为12%左右时,与纯E-51树脂相比,杂化树脂的冲击强度和断裂韧性分别提高了169.8%和35.2%,拉伸强度和弯曲强度分别提高了6.5%,10.0%,维卡软化点温度、玻璃化转变温度和热分解温度略有下降。     

Properties of poly(urea‐formaldheyde) microcapsules containing an epoxy resin

Physical properties of urea‐formaldehyde microcapsules containing an epoxy resin are presented and discussed. Microcapsules were prepared by in situ polymerization of monomers in an oil‐in‐water emulsion. Differential scanning calorimetry, thermogravimetric analysis, and scanning electronic microscopy were applied to investigate thermal and morphological microcapsule properties. Microencapsulation was detected by means of FTIR and Raman techniques. It was found that the amount of encapsulated epoxy resin as well as the extent of urea‐formaldehyde polymerization depends on the reaction temperature and the stirring speed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Phase separation during crosslinking of epoxy resin/poly(ethylene oxide) blends

Summary Poly(ethylene oxide) (PEO) was found to be miscible with uncured epoxy resin of DGEBA type (ER) as shown by the existence of a single glass transition temperature (Tg) in each blend. However, PEO with ¯Mn = 20,000 was judged to be immiscible with the highly aminecross linked ER. It was observed that the phase separation in the ER/PEO blends occurred as the crosslinking progressed. This is considered to be due to the dramatical change in the chemical and physical nature of ER during the crosslinking.     

印染废水物化处理技术研究

从工程技术和环境保护的角度,综述了印染废水物化处理技术的研究现状,分析了不同处理技术的研究内容和研究热点,指出了存在的问题并展望了其发展方向。