Syntheses of aromatic polyesters from silylated monomers

Summary Aromatic polyesters were synthesized either from silylated bisphenols and diacid chlorides or from trimethyl siloxy benzoyl chlorides by thermal condensation at 200–300°C. Yields and molecular weights were compared with those obtained by other condensation methods. The Silyl Method seems to be most useful for the synthesis of polyesters of aromatic -hydroxy acids.     

Polymerizable monomers from castor oil: II. Syntheses of some divinyl monomers

Ten divinyl monomers have been synthesized, based on commonly available products derived from castor oil, in 50–100 g lots of high purity. These were characterized by infrared spectroscopy and their purity was checked by chromatographic methods. Boiling points, refractive indices and iodine values of the products are reported. Thin layer chromatography of divinyl monomers based on decanedioic acid has also been studied.     

Polymerization of surface-active monomers: 5. Syntheses and polymerizations of anionic surface-active monomers: sodium di(10-undecenyl)sulphosuccinate and sodium n-undecyl 10-undecenylsulphosuccinate

Novel, anionic surface-active monomers, sodium di(10-undecenyl)sulphosuccinate (DUSS) and sodium n-undecyl 10-undecenylsulphosuccinate (MUSS) were prepared. The monomers were soluble in both water and apolar organic solvents on heating. DUSS and MUSS in water exhibited Kraft points at about 39°C and 48°C, respectively. The critical micelle concentrations for aqueous solutions of DUSS and MUSS at 50°C were determined to be 2.4 × 10⁻⁵ and 1.2 × 10⁻⁵ mol l⁻¹, respectively. Polymerization of the monomers in darkness and under u.v. irradiation at 50°C were studied using three different solvents, namely water, n-hexane and dioxane, giving aqueous micelles (or vesicles), reversed micelles and isotropic solution, respectively. Only traces of polymers were formed for the polymerizations in darkness, while the polymerizations under u.v. irradiation gave polymers, except for the polymerization of MUSS in dioxane. The solvents used for the polymerization were observed to exert an effect on the solubility of the polymers of DUSS and only the polymer obtained from the polymerization in water was soluble in solvents such as water and N,N-dimethylformamide. Thus, the monomer aggregation, especially for the aqueous system, was found to affect the structure of the resulting polymers.     

Anti-bredt monomers

Summary 1-Aza-3-oxabicyclo[3.3.1]nonan-2-one, an N-bridgehead bicyclic urethane, polymerized in bulk under the influence of dibutyltin oxide and p-toluenesulfonic acid. In solution the monomer polymerizes in the presence of phosphoric acid. This is only the second example of ring opening polymerization of a bicyclo[3.3.1]nonane. The driving force in the present case is thought to be the relief of strain energy in the monomer conferred by its chair-boat conformation.     

Anti-bredt monomers

Summary 1-Aza-6-oxabicyclo [3.2.1]octan-7-one 3 polymerized in bulk to polyurethane at 112–131°C with opening of the 5-membered urethane ring. Organometallic, cationic, anionic and organophosphoric initiators polymerized the strained bicyclic urethane to the polyurethane. In solution the monomer was shown to polymerize slowly under the influence of phosphoric acid. The driving force for the polymerization may be the relief of strain energy in the monomer caused by a boat conformation of the 6-membered ring.     

Syntheses and reactions of photopolymers,I. New photosensitive azo monomers,photolysis, interfacial polycondensation,viscosity measurements,photodegradation

The synthesis of new, unsymmetrically functionalized azo compounds and their incorporation into polymers is described. Their photochemical decomposition and thermal stability was studied by UV spectroscopy and differential scanning calorimetry (DSC), respectively. Chemical degradation was followed by viscosity measurements.     

含哒嗪酮的吡唑醛腙类化合物的合成

以1,4,5,6-四氢-6-哒嗪酮-3-甲酰肼和1,6-二氢-6-哒嗪酮-3-甲酰肼与1-苯基-3-芳基-4-甲酰基吡唑反应,得到相应的新化合物1,4,5,6-四氢-6-哒嗪酮-3-羰基吡唑醛腙和1,6-二氢-6-哒嗪酮-3-羰基吡唑醛腙.所有化合物的结构均经IR,1HNMR和元素分析得以证实.     

A synthetic approach to pyrazole functionalized polystyrene

Summary Polystyrene containing 20 % phenyl rings functionalized with pyrazole was obtained by acylation and subsequent reaction with N,N-dimethylformamid dimethylacetal and hydrazine and characterized by means of NMR and IR spectroscopy and elemental analysis.     

提高单体质量的措施

通过对单体转化、精馏等工序部分设备及工艺的改进，保证了单体工序长周期稳定运行，提高了单体质量，取得了明显的经济效益。     

微波辅助下4-碘吡唑衍生物的合成新方法

吡唑衍生物在碘单质和硝酸水溶液的共同作用下发生碘代反应,生成标题化合物。在微波辐射下,该方法反应速度较常规加热方法增加20倍以上,以较高产率得到了6个4-碘吡唑衍生物,收率85%～94%。     

Emulsion polymerisation of highly water-insoluble monomers

Contrary to an earlier report, monomers (e.g. p-tert-butylstyrene and octadecyl methacrylate) which are less soluble in water than styrene have been found to polymerise in emulsion using persulphate initiation. At 60°C, the order of the Interval II polymerisation rate of octadecyl methacrylate is 0.48 in persulphate concentration and 0.68 in sodium dodecyl sulphate concentration. The rate is increased by addition of methanol to the aqueous phase. Unlike styrene, p-tert-butylstyrene could not be polymerised in aqueous suspension by persulphate in the absence of emulsifier. High emulsifier-monomer ratios were used in these experiments so that it is possible that mini-emulsion droplets were a significant reaction locus.     

Electropolymerization of monomers on metal electrodes

The use of electropolymerization to coat metal electrode surfaces with polymers formed in situ was investigated in detail. Electrolysis was carried out in a three-compartment cell with fritted disk separators such that polymerization occurred in the middle compartment only. Both anodic and cathodic reactions were utilized to form coating on pretreated metal surfaces. It was shown that polymerization occurred both by vinyl polymerization of olefin monomers as well as by ring-opening reactions of cyclic monomers. The factors that control the coating thickness, the morphology of the polymer deposit, and the adhesion of the polymer formed to the metal substrates were determined. It was found that the growth of the coating on electrode followed the chain polymerization kinetics to a considerable degree. However, increased current did not necessarily lead to increased coating thickness because it also led to increased early termination of growing polymer chains to form soluble low molecular weight products. Water, because of its high surface tension, encourages physical adsorption on metal surfaces of organic monomers dissolved in it. Thus, water was found to be unique as solvent for obtaining coatings with good adhesion to metal substrates. Coatings formed were analyzed by several methods including infrared spectroscopy. Several types of bonding, other than bond formation caused by polymerization reactions, were identified. Finally, the cyclization of polyacrylonitrile was observed when the coating was obtained on aluminum cathode during electrolysis of acrylonitrile–sodium nitrate–DMF solution.     

Heterogeneous polymerization of some methacrylate monomers

It has been found that sodium metabisulphite failed to initiate the polymerization of methyl and butyl acrylates but succeeded in polymerizing methyl, ethyl, and hydroxy propyl methacrylates. All the samples of the poly(hydroxypropyl methacrylates) were crosslinked, even those prepared at low conversions. Gel permeation chromatographic analysis indicated a multinodal molecular weight distribution, suggesting the existence of more than one mechanism occurring in such a heterogeneous system. It has also been proved by electron spin resonance that the polymerization process, using sodium bisulphite as the initiator in such a system, is a radical mechanism. The use of substances such as quartz, glass powder, and kaoline powder enabled the detection of the bisulphite radicals by trapping them. Using ¹³C NMR spectroscopy, the estimated triad fractions from α-methyl peaks and from quaternary carbon peaks of the poly(methyl methacrylates) and poly(ethyl methacrylates) showed that the polymers obtained were all predominantly syndiotactic in structure, as expected. The poly(ethyl methacrylate) samples were found to have a slightly higher syndiotacticity than the poly(methyl methacrylates), also as expected. The greater bulk of the ethyl ester group relative to that of the methyl ester group probably leads to greater steric hindrance in the isotactic and heterotactic triad (i.e., in a mesodyad).     

Polymerizable monomers from castor oil. I. Vinyl monomers based on undecenoic acid

Thirty-four different vinyl monomers have been synthesized, based on 10-undecenoic acid, pyrolysis product of castor oil, in 50 to 100-g lots in high purity. These include allyl ethers and esters, vinyl ethers and esters, and acrylic and methacrylic esters, all of which were characterized by their infrared spectra; purity was checked by chromatographic methods. Boiling points, refractive indices, and iodine values of the products have been reported.     

Anionic polymerization of fluorine-containing vinyl monomers

Summary The anionic polymerization of pentafluorophenylmethyl methacrylate (PFPMA) were examined with several anionic initiators. The initiators of relatively low activity such as t-C₄H₉OK, organozinc compounds and Al(C₂H₅)₃ produced poly(PFPMA) in fairly high yields though no polymer was obtained by the initiations of n-C₄H₉Li and C₂H₅MgBr within 7 days. The anionic polymerization reactivity of PFPMA was found to be strongly affected by the pentafluorophenyl group though the e-value of PFPMA is similar to those of methyl methacrylate and benzyl methacrylate.Part 7, Polym. J. 19, 958 (1987)     

New phenothiazine-containing monomers and polymers

Summary Three new phenothiazine-containing electrono-donor monomers: methacryloyl-2-hydroxyethyl-2-(N-phenothiazinyl)propionate (i) acryloyl-2-hydroxyethyl-2-(N-phenothiazinyl) propionate (ii) and 2-(N-phenothiazinyl) propionic acid vinyl ester (iii) were synthesized and radically polymerized. The ionization potentials of poly(i), poly(iii) and of the model for the structural unit of the acrylic polymers: acetyl-2-hydroxyethyl-2-(N-phenothiazinyl) propionate determined with two small acceptors were discussed in terms of sterical hindrances.     

Branched polysilanes from tetrafunctional monomers

Tetrafunctional silicon monomers have been incorporated into soluble branched polysilanes. Tetrakis(chlorodimethylsilyl)silane has been homopolymerized to form an irregular branched polymer which may contain some spiro and some bicyclic units. This polymer shows weak absorption at 300 nm, the region of the linear polysilane chains. It emits broadly in the region from 400 to 500 nm. The copolymers of tetrakis(chlorodimethylsilyl)silane with dichlorodimethylsilane are also soluble and in the presence of l ge amount of the tetrakis monomer emit in the region from 400 to 500 nm. By contrast, copolymers with phenyltrichlorosilane emit strongly at 450 to 650 nm, due to the phenylsilane hyperbranched structure. Small amounts of tetrachlorosilane can be incorporated into soluble polysilanes. Incorporation of =Si=units into polymers withn-hexyl substituents is very inefficient but leads to minor changes in emission spectra. Incorporation into polymers with phenyl substituents affects luminescence and increases molecular weights and broadens polydispersities. Reaction with dimethyldichlorosilane provides soluble low molecular weight oligomers and polymers. Polymers prepared with a small proportion of tetrachlorosilane show absorption and emission typical for linear polymers. Polymers synthesized with higher proportion of tetrachlorosilanes emit broadly at 400 to 500 nm, indicating the presence of Si clusters. The silicon clusters entrapped into soluble polymers are very easily oxidized as seen by the siloxane peaks in²⁹Si NMR spectra and they should be treated under complete exclusion of oxygen.     

Novel self-initiating UV-curable acrylate monomers

Based on the addition reaction of hydroxyl groups and the isocyanate groups in the bi-functional monomer acroyloxyethyl isocyanate (AOI), two novel self-initiating ultraviolet (UV)-curable acrylate monomers were synthesized from benzoin and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (commercial-available Irgacure® 2959), and the products were denoted as Benzoin-AOI and 2959-AOI, respectively. The chemical structures of the products were confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The UV–visible absorption spectrum showed that the self-initiating acrylates exhibited similar maximum absorption wavelengths to both benzoin (250 nm) and Irgacure® 2959 (270 nm). When the products were continually exposed to a mercury lamp, the maximum absorption peak gradually blue shifted, showing that the products decomposed under the UV radiation. The photo differential scanning calorimetry (Photo-DSC) analysis showed that the self-initiating monomers could initiate the polymerization of 1,6-hexanediol diacrylate (HDDA) as quickly as the original photo-initiator, and the efficiency of Benzoin-AOI was slightly lower than that of benzoin, while for 2959-AOI, the efficiency remained stable after being linked to the AOI moiety. The cytotoxicity assay against fibroblasts cell line L929 showed that 2959-AOI exhibited lower cytotoxicity at low dosages but higher cytotoxicity at high dosages compared to Irgacure® 2959 after the introduction of the AOI structure.     

Well-defined organic-inorganic hybrid benzoxazine monomers based on cyclotriphosphazene: Synthesis, properties of the monomers and polybenzoxazines

Well-defined organic-inorganic hybrid benzoxazine monomers based on cyclotriphosphazene (CP) cores have been synthesized. Theses monomers possessed controllable number of organic benzoxazine moieties and biphenyl groups distributed on the inorganic ring of CP. Corresponding ring-opening polymerization under heat led to highly cross-linked polymers with different number of crosslinking sites. The ring-opening polymerization behaviors of the new benzoxazine monomers were investigated by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMA). The results indicated that the polymerization activity of the monomers depended on the number of benzoxazine moiety of corresponding monomers. Those monomers with more benzoxazine moieties resulted in higher polymerization rate. Due to the high crosslinking nature with rigid and stable inorganic CP ring and biphenyl groups in the networks, the resulted polybenzoxazines from the monomers showed excellent thermal stability, mechanic property and humidity resistance.