食用香料二烯丙基三硫和二烯丙基四硫的合成

以硫代硫酸钠、烯丙基溴和硫化钠为原料,合成了二烯丙基三硫,产率为76.4%;以一氯化硫和烯丙硫醇为原料合成了二烯丙基四硫,产率为81.0%。合成的产物通过红外光谱和气-质联用仪进行了结构鉴定。以合成的二烯丙基三硫、二烯丙基四硫和其他的含硫香料为原料,调配出了大蒜香精。     

Stabilization of thermal degradation of poly(methyl methacrylate) by polysulfide polymers

The thermal degradation of poly(methyl methacrylate) (PMMA) in the presence of polysulfide polymers, namely, poly(styrene disulfide) (PSD) and poly(styrene tetrasulfide) (PST) was studied using thermogravimetry (TG) and direct pyrolysis-mass spectrometric (DP-MS) analysis. Both PSD and PST were found to stabilize the PMMA degradation, which was explained by both radical recombination and a chain-transfer mechanism. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2149–2156, 1997     

Synergistic Effects of Polybenzimidazole and Aramide on Enhancing Flame-Retardancy and Solubility

Aromatic and functional polymers with processibility derived from biobased starting materials are prerequisite considering sustainable society. Poly(2,5-benzimidazole)s are rigid-rod polymers to show ultrahigh thermal stability such as flame retardance, while usually suffer from poor solubility. Here, poly(benzimidazole-co-amide)s are synthesized from two biobased monomers, 3,4-diaminobenzoic acid and a semirigid comonomer, 4-aminohydrocinnamic acid. The copolymers with an amide composition of 80 mol% and higher are soluble in widely used polar solvents to fabricate the films keeping high flame retardance, which is comparable with popular high-performance polymers such as aromatic polyimides, polyetheretherketone, polyphenylene sulfide, etc.     

水相合成双-[γ-（三乙氧基硅）丙基]-二硫化物

以γ-氯丙基三乙氧基硅烷(简称γ2)、硫氢化钠、硫为原料,通过加入缓冲剂控制反应体系的pH以抑制γ2的水解,同时运用相转移催化技术,在水相中合成了双-[γ-(三乙氧基硅)丙基]二硫化物(简称Si-75)。主要考察了n(NaHS)∶n(S)、n(γ2)∶n(Na2Sx)、n(Na2CO3)∶n(NaHS)、反应温度、相转移催化剂用量等对合成工艺的影响,最终制得的Si-75外观呈浅黄色,产率为95.4%,w(S)=13.5%。     

Characterization of synthesized poly(aryldisulfide) through interfacial polymerization using phase-transfer catalyst

A new polysulfide polymer was synthesized from 1,4-bis(chloromethyl)-benzene and sodium disulfide by an interfacial polycondensation technique in the presence of tetrabutyl ammonium bromide, methyltributyl ammonium chloride and benzyl triethyl ammonium chloride as phase-transfer catalysts (PTC). The effect of PTC on the kinetics of polymerization was investigated. Structures of this aromatic polysulfide were confirmed through elemental analyses, attenuated total reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, an X-ray diffraction technique, and a nuclear magnetic resonance spectroscopy method. The thermal behavior of this polymer was also characterized by differential scanning calorimetry and thermogravimetric analysis. The solubility of prepared polymer was critically dependent on the identity of the solvent.     

新型橡塑硫化助剂的合成

以九水硫化钠、硫粉、γ-氯丙基三乙氧基硅烷为原料,甲苯、乙醇作溶剂,合成了双-(γ-三乙氧基硅丙基)二硫化物。讨论了反应物比例、溶剂用量、反应温度和时间等因素对产率的影响。结果表明,最佳工艺条件:硫与九水硫化钠的物质的量比为1.05:1,甲苯与九水硫化钠的物质的量比为36:1,γ-氯丙基三乙氧基硅烷与过硫化钠的物质的量比为2.1:1,无水乙醇与过硫化钠的物质的量比为5.0:1,反应温度为80℃,反应时间为4 h。最终制得的产品外观为淡黄色,类乙醇香味,产率为95.63%,含硫量达13.8%,产品贮存时间长。     

Crosslinking of poly(arylene disulfide)s and poly(arylene sulfane)s derived from cyclic(arylene disulfide) oligomers

Cyclic(arylene disulfide) and polycyclic(arylene sulfide) oligomers were synthesized by catalytic oxidation of arylenedithiols or arylenetrithiols with oxygen in the presence of a copper‐amine catalyst. These cyclic(arylene sulfide) oligomers can undergo free radical ring‐opening polymerization at an elevated temperature in the melt or solution. Polycyclic(arylene sulfide) oligomers can be used to crosslink poly(arylene disulfide)s and poly(arylene sulfane)s derived from cyclic(arylene disulfide) oligomers and elemental sulfur. The crosslinking reactions were investigated by differential scanning calorimetry and by solubility of the cured products. The minimum concentrations of polycyclic(arylene sulfide) oligomers for producing a well crosslinked poly(arylene disulfide) and poly(arylene sulfane) are 7 wt % and 10 wt %, respectively. The crosslinking reactions between poly(arylene disulfide)s, poly(arylene sulfane)s, and triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione (TTT) were also investigated. TTT is more efficient for crosslinking than the synthesized polycyclic(arylene disulfide) oligomers. The crosslinkable poly(arylene disulfide)s and poly(arylene sulfane)s could be potentially used as high temperature coatings, sealants, adhesives, and as matrices for high performance thermoset composites. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3069–3077, 1999     

Synthesis, characterization, and reactivity ratio studies on new sulfide copolymers containing ethylbenzene units

Soluble new sulfide copolymers were synthesized readily by the polycondensation of ethylene dibromide (EDB) (or methylene dibromide (MDB)) with styrene dibromide (SDB) and sodium sulfide (Na₂S) in the presence of phase transfer catalyst. The copolymers were characterized by using Fourier transform-infrared, ¹H NMR, ¹³C NMR, gel permeation chromatography, and thermogravimetric analysis (TGA) techniques. The copolymer composition obtained from the ¹H NMR spectra led to the determination of reactivity ratios. The analysis of reactivity ratios revealed that both EDB and MDB are more reactive than SDB towards Na₂S, and copolymers formed are random in nature. Furthermore, it also gave an insight on the microstructure of the copolymers that both poly (ethylene sulfide-co-styrene sulfide) (p(ES-co-SS)), and poly(methylene sulfide-co-styrene sulfide) (p(MS-co-SS)) copolymers have more of blocky structure with increase in the concentration of ethylene sulfide (ES) or methylene sulfide (MS) units in the respective copolymers. The TGA was used to find out the thermal stability of these polymers. The XRD data indicated an increase in the amorphous content of the copolymers with an increase in the concentration of styrene sulfide (SS) units and thereby resulting in most of these copolymers being soluble in common organic solvents. The solubility and molecular weight of the polymers formed were dependent on the concentration of SDB taken in the feed.     

Synthesis, characterization, thermal degradation, and comparative chain dynamics studies of weak-link polysulfide polymers

Synthesis, spectroscopic and thermal characterization of two new classes of polysulfide polymers: poly[1-(phenoxymethyl) ethylene polysulfide] (PPMEP), and poly[1-(phenoxy) ethylene polysulfide] (PPEP) is presented. The direct pyrolysis mass spectrometry (DP-MS) technique, used to study the thermal degradation behavior of these polysulfide polymers, indicated that the polymers underwent degradation through the weak-links scission. The thermal stability of the polysulfide polymers decreased as the “rank” (number of sulfur atoms in the polysulfide linkage; n = 1, 2, 4) increased. The main-chain flexibility of these polysulfide polymers in terms of their ¹³C NMR spin-lattice relaxation time (T ₁ ) measurements on the backbone methine (-CH-) and methylene (-CH₂-) carbons are reported here for the first time. A comparative study of the solution chain dynamics indicated that it increased as “rank” of the polysulfide linkages decreased as well as by introducing side chain spacers such as, ether (-O-) or methyleneoxy (-CH₂O-) groups.     

二硫化钠法合成巯基乙酸的研究

概述了巯基乙酸的用途、合成方法 ,研究了二硫化钠法合成巯基乙酸的主要影响因素。实验从硫化钠、硫磺等基本原料出发 ,首先制得二硫化钠溶液 ,然后将二硫化钠同氯乙酸钠反应合成二硫代甘醇酸 ,最后用硫化钠溶液还原得到巯基乙酸。试验探讨了反应物料配比、反应温度、pH值、反应时间等因素对反应转化率的影响 ,实验结果表明该法的转化率可达 96 %左右 ,其具体反应条件如下 :硫化钠∶硫∶氯乙酸钠 (mol) =1.2∶1.4 4∶1.0 0 ,pH值 =7.5,合成二硫代甘醇酸的温度为 35℃ ,时间为 30min     

双-[3-(三乙氧基)硅丙基]四硫化物的合成及应用

用γ 氯丙基三乙氧基硅烷 (CPOS)、钠、硫及含硫化合物合成双 [3 (三乙氧基 )硅丙基 ]四硫化物 ,找出了最佳工艺条件 :m(CPOS)∶m(Na)∶m(Na2 S)∶m(S) =72∶(2 .5～ 3)∶15∶(15～ 18) ;温度控制在 75℃ ;回流 4h。w (S) =2 2 3% ,转化率达 96 %以上。经多家用户检验和使用 ,在橡胶中补强和粘合作用良好 ,质量稳定     

Desulfurization of aromatic polysulfides with triphenylphosphine

The room temperature reaction of bis(4-methylbenzene) di- (3), tri- (4) and tetrasulfide (5) with triphenylphosphine has been followed by ¹H NMR. Mechanistic aspects of the cleavage of 3 and the desulfurization of 4 and 5, with concomitant formation of triphenylphosphine sulfide, are discussed. While tetrasulfide 5 is desulfurized over 10× faster than trisulfide 4, preliminary experiments indicate that 5 is not sufficiently reactive to efficiently transfer a sulfur atom to oligodeoxyribonucleotides.     

有机硫化剂研究进展

加氢催化剂的预硫化处理是催化加氢工艺必不可少的环节,硫化剂的性能优劣对此过程有重要影响。比较了无机硫化剂、固体硫化剂和有机硫化剂,指出有机硫化剂因具有毒性较低、分解温度宽和油溶性好等优势而被广泛应用,列举几种工业常用的有机硫化剂,并评述其合成工艺。根据有机二硫或多硫化物中烃基的来源,有机硫化剂合成主要有以烯烃、单质硫和硫化氢为原料、以烯烃与单质硫为原料、以烯烃与卤化硫为原料、以硫醇和单质硫为原料及以烷基化试剂、硫和硫化钠或硫脲为原料等5种合成路线,详细介绍各种不同合成路线的反应机理、反应条件、难易程度、突出优势、存在不足和工业应用情况,以烷基化试剂、硫和硫化钠或硫脲为原料的合成路线因转化率高及反应条件温和而逐渐成为制备有机硫化剂的重要方法。此外,多种有机硫化剂的混合使用可以弥补单一有机硫化剂的不足,利用廉价和富含烯烃的催化裂化汽油以及单质硫为原料合成混合有机多硫化物将是今后研究的重要趋势和主要发展方向,应用前景广阔。     

Synthesis and characterization of soluble polymer ligands possessing sulfide side chains

Soluble polymer ligands possessing aryl monosulfide side chains [poly(4-vinylphenylmethyl sulfide) (PVPMS)], alkyl monosulfide side chains [poly(4-vinylbenzylmethyl sulfide) (PVBMS)] and branched tetrasulfide side chains [poly(7-(4′-vinylbenzyloxy)-2,5,9,12-tetrathiatridecane) (PTeSSD)] were prepared by radical polymerization of the corresponding monomers. These polymer ligands had specific binding abilities for soft acids only, such as Ag(I) and Hg(II) ions. The tetrasulfide-type polymer ligand, PTeSSD, bound the metal ion only by the tetrasulfide side chain itself. The monosulfide-type polymer ligands, PVPMS and PVBMS, bound the metal ion by co-operative interaction between their monosulfide side chains. The resulting polymer-Ag(I) complexes were soluble in organic solvents. Interestingly, a polyester cloth coated with the polymer-Ag(I) complex exhibited significant antibacterial activity against Staphylococcus aureus.     

Synthesis and characterization of poly(methylene disulfide) and poly(ethylene disulfide) polymers in the presence of a phase transfer catalyst

Poly(methylene disulfide) and poly(ethylene disulfide) were synthesized from the polycondensation of methylene dichloride and ethylene dichloride monomers, respectively, in the presence of benzyltriethylammonium chloride as a phase transfer catalyst. The structures of the synthesized polysulfides were confirmed via the elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy and X-ray diffraction techniques. Moreover, the thermal behaviors of synthesized poly(methylene disulfide) and poly(ethylene disulfide) were characterized using differential scanning calorimetry and thermogravimetric analysis methods. The synthesized poly(methylene disulfide) and poly(ethylene disulfide) have molecular weights of about 2262 and 2863 g/mol, respectively. In addition, the polymers have crystalline structures absorbed in the amorphous sections. However, the d-spacing of polymers’ crystalline parts was different. Moreover, poly(methylene disulfide) and poly(ethylene disulfide) have a two- and one-step degradation behavior, respectively.     

二硫化钼纳米微粒及其单层悬浮液的制备

利用硫化铵与钼酸钠为原料,制备出非晶态三硫化钼微粒,在氢气氛下煅烧晶化该非晶态三硫化钼,得到30-50nm的片状二硫化钼微粒.将制备的纳米二硫化钼微粒与正丁基锂的正己烷溶液反应48小时,然后将固体产物浸入水中,在超声分散下获得了稳定的纳米二硫化钼悬浮液,最后用XRD、TEM及HRTEM对产物进行了表征.     

The effect of soft‐segment structure on the properties of novel thermoplastic polyurethane elastomers based on an unconventional chain extender

Thermoplastic polyurethane elastomers (TPUs) are now widely used because of their excellent properties that include high tensile and tear strength, and good abrasion, impact and chemical resistance. TPUs are multiblock copolymers with alternating sequences of hard segments composed of diisocyanates and simple diols (chain extenders) and soft segments formed by polymer diols. Commonly used hard segments for TPUs are derived from 4,4′‐diphenylmethane diisocyanate (MDI) and aliphatic diols. The aim of our research was to examine the possibility of obtaining TPUs with good tensile properties and thermal stability by using an unconventional aliphatic‐aromatic chain extender, containing sulfide linkages. Three series of novel TPUs were synthesized by melt polymerization from poly(oxytetramethylene) diol, poly(ε‐caprolactone) diol or poly(hexane‐1,6‐diyl carbonate) diol of number‐average molecular weight of 2000 g mol^?1 as soft segments, MDI and 3,3′‐[methylenebis(1,4‐phenylenemethylenethio)]dipropan‐1‐ol as a chain extender. The structure and basic properties of the polymers were examined using Fourier transfer infrared spectroscopy, X‐ray diffraction, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. It is possible to synthesize TPUs from the aliphatic‐aromatic chain extender with good tensile properties (strength up to 42.6 MPa and elongation at break up to 750%) and thermal stability. Because the structure of the newly obtained TPUs incorporates sulfur atoms, the TPUs can exhibit improved antibacterial activity and adhesive properties. Copyright © 2011 Society of Chemical Industry     

Pendant crosslinked poly(aryl ether sulfone) copolymers sulfonated on backbone for proton exchange membranes

A series of sulfonated poly(aryl ether sulfone) copolymers containing phenyl pendant groups with sulfonic acid groups on the backbone were synthesized through condensation polymerization. The degree of sulfonation (DS) of the copolymers was controlled by changing the feed ratios of sulfonated to unsulfonated monomers. Post‐crosslink reactions are carried out with 4,4′‐thiodibenzoic acid (TDA) as a crosslinker and the carboxylic acid groups in TDA can undergo Friedel–Craft acylation with the phenyls pendent rings in sulfonated poly(arylene ether sulfone)s copolymers to prepare polymer electrolyte membranes for fuel cell applications. The chemical structures of crosslinked and uncrosslinked sulfonated poly(arylene ether sulfone)s copolymers (SPSFs and CSPSFs) were characterized by FTIR, ¹H NMR spectra. The thermal and mechanical properties of the membranes were characterized by thermogravimetric analysis and stress–strain test. The dependence of water uptake, methanol permeability, proton conductivity, and selectivity on DS was studied. Transmission electron microscopic observations revealed that SPSFs and CSPSFs membranes form well‐defined microphase separated structures. POLYM. ENG. SCI., 54:2013–2022, 2014. © 2013 Society of Plastics Engineers     

Synthesis of new imidazole-based monomer and copolymerization studies with methyl methacrylate

In this study, copolymers were synthesized using methyl methacrylate (MMA) and 2-allyloxymethyl-1-methylimidazole (AOMMI) monomers at various ratios. For this purpose, hydroxyl end-functionalized imidazole was initially prepared with 1-methylimidazole and then it was used to prepare allyl-derived imidazole monomers. Finally, the synthesis of copolymers (poly(MMA-co-AOMMI)) was carried out using different proportions of commercial MMA and AOMMI monomers. Photopolymerization method was preferred as polymerization technique. The polymerization was carried out in solvent-free medium and benzophenone was used as the initiator. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR) and elemental analysis were used for the structural characterization of the obtained copolymers. Molecular weights and the thermal behaviour of the synthesized copolymers were analysed with gel permeation chromatography (GPC) and thermogravimetry (TG) techniques, respectively. The surface of the products was tried to be illuminated using scanning electron microscopy (SEM). According to the obtained FTIR, NMR and elemental analysis results, the copolymers were successfully synthesized. A number average molecular weights of poly(MMA-co-AOMMI) samples were found 13,500 (MMA:2/AOMMI:1), 16,600 (MMA:1/AOMMI:2) and 17,300 (MMA:1/AOMMI:1) according to the mixing ratios. When the thermal stabilities of the synthesized copolymers were observed, it has been seen that those containing imidazole had higher stability than the neat PMMA.     

Synthesis of complex architectures of comb block copolymers

The synthesis of comb block copolymers by ring opening metathesis polymerization (ROMP), ring opening polymerization (ROP), and atom transfer radical polymerization (ATRP) is described. Block copolymers were synthesized by the ROMP of oxanorbornene and norbornene monomers followed by hydrogenation of the olefins along the backbone. One block of these diblock copolymers possessed initiators either for the ROP of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione or the ATRP of butyl acrylate. The synthesis and characterization of comb polymers with arms composed of poly(lactic acid) and poly(butyl acrylate) are described. These polymers had well-defined peaks in the size exclusion chromatography spectra which indicated that no homopolymers were synthesized. A comb block copolymer with polymeric arms of poly(styrene-b-vinylpyridine) is described. Vinylpyridine was polymerized from a comb polymer with poly(styrene) arms by ATRP at high dilution of the comb polymer.