聚甲基丙烯酸缩水甘油酯疏水纳凝胶的制备与表征

采用乳液聚合法制备了聚甲基丙烯酸缩水甘油酯疏水纳凝胶。通过透射电子显微镜、傅里叶红外光谱和动态激光光散射等测试对其结构和形貌进行了表征,对疏水纳凝胶形成过程规律和对温度、pH和时间稳定性进行了考察,并探究了单体浓度、交联剂含量和乳化剂浓度对纳凝胶粒径的影响规律。结果表明：所得疏水纳凝胶具有粒径均一、分散稳定和溶胀性能好等优点。疏水纳凝胶粒径在一定温度和pH范围内无变化,在30天内粒径从76nm增至116nm,zeta电位随温度升高而增加,其值稳定在-90~-30mV之间,说明是一种较为稳定的凝胶体系。在实验范围内,纳凝胶粒径随单体甲基丙烯酸缩水甘油酯和交联剂二甲基丙烯酸乙二醇酯浓度的增加从80nm增至250nm,随乳化剂浓度增加从230nm降至60nm。     

Synthesis and fluorescence studies of dual-responsive nanoparticles based on amphiphilic azobenzene-contained poly (monomethyl itaconate)

Here photo- and pH-responsive behavior of polymer micelles formed by synthesized azo-modified poly (monomethyl itaconate)s (PMMI-Azo) with appropriate amounts of azobenzene side groups (DS_Azo) were reported. The PMMI-Azo polymer with DS_azo?=?20 was used for the preparation of micelles using dialysis method. Self-assembly behavior of the PMMI-Azo was studied by transmission electron microscopy (TEM), fluorescence spectroscopy, dynamic light scattering (DLS) and UV–Vis spectrophotometry techniques. It was found that the PMMI-Azo polymers self-assembled into spherical micelles with core-shell structures. TEM images and DLS analysis of the PMMI-Azo-20 micelles showed regular spherical micelles which increased in size and polydispersity index after UV irradiation, caused by isomerization. It was also found that with increasing the polymer concentration, the fluorescence intensity decreased obviously which could be attributed to the interactions between the closely located pyrene and azobenzene in the micelles core. Experimental results suggested that the micellization-enhanced fluorescence was caused by a slowdown in the rate of the trans-to-cis photoisomerization. Furthermore, it was found that the fluorescence intensity of the aqueous micellar solutions was sensitive to stimulus such as pH change and UV light irradiation, as a result of alteration in aqueous micellar association. The results clearly indicated the role of UV irradiation and pH in the state of the polymer micellar association which is responsible for fluorescence intensity.     

聚二烷基硅烷的合成及其表征

以二甲基二氯硅烷、二苯基二氯硅烷为原料，通过Wurtz还原反应合成出聚二甲基硅烷、聚二苯基硅烷，并用UV、^1H NMR、FT—IR以及GPC、DSC—TGA等方法进行了光谱分析和结构表征。     

Synthesis and characterization of poly(N-propionyl)iminoethylene

Summary The cationic polymerization of 2-ethyl-2-oxazoline using CH₃I as initiator at different monomer/initiator ratios, temperatures, solvents and times of polymerization was carried out. The effect of these variables on the polymerization yield and viscosity of the polymers was studied. The poly(N-propionyl)iminoethylene was hydrolyzed in acid medium obtaining a linear poly(ethyleneimine) (PEI). All the polymers were characterized by elemental analysis, IR,¹H NMR, and¹³C NMR spectroscopy.     

Synthesis and characterization of poly(siloxane-urethane)s

A series of polyurethane block copolymers based on hydroxy-terminated polydimethylsiloxane and poly(propylene glycol) soft segments of molecular weights 1818 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-diphenylnethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize polydimethylsiloxane-based polyurethanes (PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure polydimethylsiloxane-based polyurethane and poly(propylene glycol)-based polyurethane (PPG-PU), (mixed polyol)-based block copolymers and blends of PDMS-PU and PPG-PU were synthesized, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based copolymers and lower hard-segment content blends, macro-phase separation occurred, but blends with higher hard-segment contents showed significant reduction in amounts of phase separation.     

Synthesis and characterization of poly(1,8-diethynylnaphthalene)

Summary The cyclopolymerization of 1,8-diethynylnaphthalene(DEN) and its copolymerization with diethyl dipropargylmalonate(DEDPM) were carried out by various transition metal catalysts. MoCl₅-based catalyst was found to be very effective and gave almost a quantitative polymer yield. The resulting dark-brown homopolymer(PDEN) was partially soluble in chloroform, tetrahydrofuran, and dimethyl sulfoxide, whereas copolymer (1:1) with number avaerage molecular weight of 2.1x10⁴ by GPC showed good solubility in those solvents. The structure of the polymers was analysed by IR, NMR, and UV-VIS spectroscopies. From the spectral and solubility data, it is proposed that cyclized products with the conjugated system are formed. Room temperature conductivities of the I₂-doped homo and copolymer were found to be about 7.5x10^-3 and 5.1x10^-3 S/cm, respectively.     

羟基聚甲基苯基硅氧烷的合成与表征

以甲基苯基二乙氧基硅烷(MPS)和八甲基环四硅氧烷(D4)为原料,在酸性条件下水解MPS,水解产物在碱催化下与D4开环共聚合制备了高苯基含量羟基封端的聚甲基苯基硅氧烷齐聚物(PMPS)。用GPC测试了相对分子质量及其分布;用FTIR,^1H—NMR对其结构进行了表征。结果发现,在试样PMPS—6中,苯基结构单元与非苯基结构单元组成比为0．65,硅羟基质量分数为0．5％。     

Synthesis and characterization of antiseptic-based poly(anhydride-esters)

Summary Poly(anhydride-esters) were prepared from catechol, fenticlor and hexachlorophene. The molecular weights (M_w) of the polymers were typically >10,000 Da with glass transition temperatures (T_g) ranging from 23 to 84 °C. The thermal characteristics of the polymers paralleled the melting temperatures of the chemically incorporated antiseptic molecules. The in vitro release of the chemically incorporated antiseptic molecules were monitored over a 12 week period. For comparison, the in vitro release of physically admixed antiseptic molecules were also observed. After 12 weeks, the polymers were not completely degraded with drug release ranging from less than 1 to 55%. Sessile-drop contact angles indicated that the polymers were relatively hydrophobic, contributing to the slow polymer degradation rates.     

Synthesis and characterization of poly(N-tert-alkylmaleimide)s

N-tert-Butylmaleimide (tBMI) polymerized readily in the presence of a radical initiator in spite of its bulky N-substituent to give a high molecular weight and less-flexible poly(substituted methylene). From kinetic investigation for the polymerization of tBMI with 2,2-azobisisobutyronitrile (AIBN) in benzene, it was revealed that the rate of polymerization (R _p) was expressed as R _p=k [AIBN]^0.51[tBMI]^1.4, and the overall activation energy was 99.6 kJ/mol. The high polymerization of tBMI was assumed to result from the decrease in the rate of bimolecular termination between rigid polymer radicals bearing a bulky substituent. The flexibility of the polymer chain was examined by the viscometric and light scattering methods, and the effect on the polymerization reactivity was discussed.     

Synthesis and characterization of adamantane-containing poly(enaminonitriles)

The first aliphatic bis(chlorovinylidene cyanide) monomer, 1,3-bis(1-chloro-2,2-dicyanovinyl)adamantane, has been synthesized and polymerized with appropriate diamines to give adamantane-containing aromatic-aliphatic and all aliphatic poly(enaminonitriles) (PEANs) via vinylic nucleophilic substitution polymerization. The PEANs showed excellent solubility in polar aprotic solvents and good thermal stability (10% weight loss in air > 320 °C), despite the aliphatic contents of the polymers. Solution inherent viscosities of 0.23-0.90 dL/g were obtained.Three other new PEANs containing the adamantane-based cardo group were also synthesized via vinylic nucleophilic substitution polymerization from the adamanaine-containing cardo diamine 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane. The cardo PEANs showed better solubility in common organic solvents than the corresponding cardo polyamides. They also showed good thermal stabilities (10% weight loss in air > 339 °C) comparable to those of the corresponding cardo polyamides.     

Synthesis and characterization of new poly(siloxysilanes)

The efficient synthesis of two new monomers, vinyltris(dimethylsiloxy)silane (2) and tris(dimethylvinylsiloxy)silane (3), was developed. Hydrosilation of these new A–B₃ monomers affords highly branched starburst poly(siloxysilane) polymers. Polymerization of2 yields a polymer structure that has siliconhydride functional groups on the outer sphere. Polymerization of3 yields a polymer that has the same hyperbranched poly(siloxysilane) core as the polymer produced from2, but the outer sphere contains vinyl moieties. The presence of silicon-hydride or vinyl groups on the surface of both polymers allows functionalization of these materials with a wide variety of reagents.Presented at the XXVIth Silicon Symposium, Indiana University—Purdue University at Indianapolis, March 26–27, 1993.     

聚4-乙烯基吡啶的合成与表征

以过氧化二苯甲酰(BPO)为引发剂,用悬浮聚合的方法制备了较高相对分子质量的聚4 乙烯基吡啶(P4VP)。通过对聚合产物相对分子质量测试结果的分析,研究了单体与水的体积比、引发剂用量、分散剂用量、反应时间、反应温度、搅拌速度等因素对4 VP聚合反应的影响。结果表明,聚合时间为1h、聚合温度为60℃、引发剂的质量分数(占单体量)为0.8%左右、分散剂的质量分数(占单体量)为0.6%、搅拌速度为300r/min时,P4VP的重均分子量就能达到6×105～9×105。另外,采用紫外吸收光谱(UV)、红外吸收光谱(IR)、核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)、热重 差热分析(TG DTA)等测试手段研究了P4VP的结构和性能。     

Synthesis and characterization of poly(2-methylaziridine)

Summary The cationic polymerization of 2-methylaziridine using boron trifluoride etherate as initiator at different monomer/initiator ratios, temperatures, solvents, and times of polymerization was carried out. The effect of these variables on the polymerization yield and viscosity of the polymers was studied. All the polymers were characterized by elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR spectroscopy, thermogravimetric analyses and differential scanning calorimetry.     

Synthesis and characterization of poly(o-phenylene carboxylates)

The homopolycondensation of salicyloyl chloride was carried out in presence of nitrobenzene as a solvent to prepare poly(o-phenylene carboxylates). The resulting polyesters when treated with Friedel-Crafts catalyst do not undergo Fries migration. This is contrary to reported investigations. The synthesized polyesters were insoluble in common organic solvents and are characterized by IR, viscosity study and thermal analysis. Kinetic parameters are evaluated from DTA traces.     

Synthesis and characterization of poly(tetramethyldisiloxane-ethynylenephenyleneethynylene) resins

Poly(tetramethyldisiloxaneethynylenephenyleneethynylene) resins were synthesized by polycondensation reactions of the bismagnesium derivative of p- or m-diethynylbenzene with 1,3-dichlorotetramethyldisiloxane. The molecular weights of the resins were determined by gel permeation chromatography. The structures of the resins were verified by ¹H, ¹³C, and ²⁹Si NMR as well as FT-IR spectroscopy. The thermal behavior of the resins was traced by differential scanning calorimetry (DSC). The resins can be thermally crosslinked through the acetylene groups to produce highly crosslinked resins which were thermally stable up to 539 °C in both nitrogen and air. Hard, black, and glassy ceramics were obtained after the sinter of the crosslinked resins at 1,450 °C. The polymers have a potential application as matrix materials for advanced composites and ceramic precursors.     

嘧啶与联苯胺类共聚物的合成及表征

采用NaClO氧化联苯二胺成功合成了N,N′-二氯苯醌二亚胺、3,3′-二甲基-N,N′-二氯联苯醌二亚胺和3,3′-二甲氧基-N,N′-二氯联苯醌二亚胺,将其分别与4,6-二氯嘧啶采用金属配合物催化法共聚合,合成了3种新型共聚物:聚(N,N′-二氯联苯醌二亚胺-嘧啶)、聚(N,N′-二氯-3,3′-二甲基联苯醌二亚胺-嘧啶),聚(N,N′-二氯-3,3′-二甲氧基联苯醌二亚胺-嘧啶)。采用傅里叶变换红外光谱、紫外-可见吸收光谱、循环伏安、充放电对共聚物进行结构与性能测试。结果表明:该类共聚物具有一定的电化学活性,每种共聚物均在-0.2~1.0 V出现一对氧化还原峰;聚(N,N′-二氯苯醌二亚胺-嘧啶)、聚(N,N′-二氯-3,3′-二甲基联苯醌二亚胺-嘧啶,聚(N,N′-二氯-3,3′-二甲氧基联苯醌二亚胺-嘧啶)的比电容分别为46.2,34.4,23.9 F/g。     

含聚环氧乙烷链段梳形结构聚(异戊二烯-g-苯乙烯)的合成与表征

以聚苯乙烯(PS)大分子单体和异戊二烯为共聚单体,四氢呋喃为调节剂,正丁基锂为引发剂,三异丁基铝为助引发剂,脂肪族缩水甘油醚为官能化改性剂,采用一锅法经活性负离子共聚合制得以聚异戊二烯为主链、PS为规整侧链,且末端含星形聚环氧乙烷链段的极性化梳形聚(异戊二烯-g-苯乙烯-s-环氧乙烷)(PI-g-PS-s-PEO),利用凝胶渗透色谱仪、傅里叶变换红外光谱仪、差示扫描量热仪等对所制备的PI-g-PS-s-PEO进行了表征,并考察了PI-g-PS-s-PEO中聚环氧乙烷链段(PEO)质量分数(w_PEO)的影响因素。结果表明,产物具有分子结构可设计、分子量分布窄等优点。此外,PS大分子单体分子量对w_PEO无影响,减小缩水甘油醚分子量、增加其用量及延长封端反应时间均可提高w_PEO,且w_PEO在0.1%～1.8%可调。     

Synthesis and characterization of poly(urethane-sulfone)s networks

ABSTRACT

New poly(urethane-sulfone)s networks were prepared by the [3 + 2] dipolar cycloaddition of azidomethyl polyethersulfone to urethane-bismaleimides based on various polyols different by their structure and molecular weight. The chemical structure of these polymers was confirmed by the Fourier transform infrared and nuclear magnetic resonance spectroscopy. The new polymers were characterized using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, as well as by stress-strain and water contact angle measurements.     

Synthesis and characterization of poly(vinyl alcohol) carbonate

Poly(vinyl alcohol) (PVA) was reacted with dimethyl carbonate (DMC) to prepare PVA carbonate (PVAC), which is considered to have three structures, cyclic carbonate (I), monocarbonate (II) and crosslinking carbonate (III). Though the reaction proceeded easily in dimethyl sulfoxide at 120 °C without any catalyst, the yield of the ethanol‐insoluble part of the products was less than that with the reaction containing a catalyst such as tetrabutylammonium bromide (TBAB). TBAB concentration did not affect the rate of carbonic esterification but affected the yield of the ethanol‐insoluble part. The rate of carbonic esterification increased with an increase in reaction temperature, and the activation energy of this reaction was 114 kJ mol⁻¹. Carbonic esterification under reduced pressure showed a larger degree of esterification than that of the reaction under atmospheric pressure. PVAC was soluble in water at a low degree of carbonic esterification (DC) but became insoluble as DC increased. The thermal property of PVA reduced by the carbonic esterification was improved as DC increased. © 2000 Society of Chemical Industry