Synthesis and mesomorphic behavior of poly(methylsiloxane)s and poly(methylsiloxane-co-dimethylsiloxane)s containing oligooxyethylene spacers and mesogenic side groups

Summary The synthesis and characterization of poly(methylsiloxanes)s and poly(methylsiloxane-co-dimethylsiloxane)s containing either bis(ethylene oxide) or tris(ethylene oxide) flexible spacers and either 4-methoxy-4-hydroxybiphenyl a mixture containing a 1:1 ratio of 4-methoxy-4-hydroxy--methylstilbene and 4-hydroxy-4-methoxy--methylstilbene, or 4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]phenol mesogenic groups, in all combinations, is presented. All polymers and copolymers display smectic mesomorphism. The dependence of phase transition temperatures on the spacer length and copolymer composition is described.     

Synthesis and dipole-dipole interaction-induced mesomorphic behavior of poly(oxyethylene)s containing (n-octylsulfonyl)alkylthiomethyl or (n-octylsulfonyl)alkylsulfonylmethyl side groups

Two series of ((n-octylsulfonyl)alkylthio)methyl-substituted poly(oxyethylene)s ((-OCH₂CHR-)_n, where R=-CH₂S(CH₂)_MSO₂(CH₂)₈H) (OTP-M, M=3,4,5,6,7,9,12), and ((n-octylsulfonyl)alkylsulfonyl)methyl-substituted poly(oxyethylene) ((-OCH₂CHR-)_n, where R=-CH₂SO₂-(CH₂)_MSO₂(CH₂)₈H) (OSP-M, M=3,4,5,6,7,9,12), were synthesized using polymer analogous reactions from poly(epichlorohydrin) to study the effect of dipole-dipole interactions of the sulfone groups (SO₂) on the ordered structures of the poly(oxyethylene) derivatives. The ordered phases of these polymers were studied using polarizing optical microscopy, X-ray diffraction, differential scanning calorimetry and IR spectroscopy. OTP-Ms and OSP-3 showed ordered phases originated from side chain crystallization, while OSP-Ms except OSP-3 showed liquid crystalline behavior. The poly(oxyethylene) derivatives with M=5,6,7 had double-layer structures, while the polymers with M=3,4,9,12 had intercalating double-layer structures at room temperature. The layer structures of the poly(oxyethylene) derivatives were found to be affected by the positions of the side chain sulfone groups which can generate strong dipole-dipole interactions.     

Synthesis and characterization of poly(vinylether)s with pendant mesogenic groups

Two different methods of synthesis were examined for the preparation of poly(alkylvinylether)s with pendant 4-cyano-4-oxy-biphenyl mesogenic groups attached to side chains of different length: a) anchoring of the mesogenic group onto an alkylvinylether monomer followed by polymerization or b) synthesis of the corresponding poly(chloroalkylvinylether)s and chemical substitution of the pendant chlorine by the mesogenic groups. Polymerization were performed with initiating systems based on activated iodide. Much better control of MW and MWD of the final polyvinylether chains was obtained when process b) was applied. Polymers with 2 and 4 carbons in the spacer do not show liquid crystalline properties. It is only with polymers having six carbon atoms in the spacer that mesophases were observed. Those issued from process b) give two distinct mesophases: a smectic A phase in the high temperature range and a smectic C phase for the low one. Polymers synthetized from process a) present only the smectic A phase. The effects of molecular weights and molecular weight distributions on the liquid crystalline properties have been examined and are discussed.     

Oligomeric poly(imide-amides)s containing side 1,8-naphthalimidyl groups: synthesis and characterization

Poly(imide-amide)s (PIAs) were synthesized from isophthalic acids, which have in position 5 a bulky group like 1,8-naphthalimidyl bonded to amino acids as flexible spacers, and the diamine bis(4-aminophenyl)diphenylsilane, which provides a polar group in the main chain. Glycine, l-alanine, l-phenylalanine, l-valine and p-aminobenzoic acid were used as amino acids. Polymers were obtained according to the Yamazaki method and characterized by elemental analysis, optical activity, IR and ¹H, ¹³C and ²⁹Si NMR spectroscopy. PIAs were soluble in aprotic polar solvents but not in common organic solvents, and obtained with low η _inh values, which was an indicative of low molecular weights species, probably of oligomeric nature. According to the polymeric structure, the only difference between PIAs is the structure of the amino acid residue, and in this sense it was possible to see an increase of the T _g values when the volume of the amino acid residue also increased, due to the lower possibility of internal mobility of the side chains. The higher Tg value was obtained with the PIA-e, which includes an aromatic ring as a side chain, derived from p-aminobenzoic acid. PIAs, in spite of the good TDT values obtained, were not thermally stable in the sense that the 10 % of weight lost was obtained at lower temperature than 400 °C, with the exception of PIA-e derived from p-aminobenzoic acid. However, there was an increase of the TDT values when the volume of the amino acid residue increases. The PIAs do not show good UV–vis transparence probably due to the low free volume of those including an aliphatic amino acid residue.     

Synthesis and thermosensitive behavior of dextran graft copolymers containing poly(N-vinylcaprolactam) side chains

New graft copolymers were synthesized by grafting N-vinylcaprolactam onto dextran. Their composition and structure were investigated by elemental analyses, infrared spectra and thermogravimetric analyses. By optical transmittance measurements, it was found that the aqueous solutions of these graft copolymers showed a temperature-dependent transmittance change due to the introduction of thermosensitive poly(N-vinylcaprolactam) graft chains. Moreover, the lower critical solution temperature (LCST) of the graft copolymer in aqueous solution was dependent on its grafting extent and concentration. The LCST value was found to increase with the increase of the grafting extent and decrease with the increase of the copolymer concentration. With these stimuli-response properties, such polysaccharide derivative may hold potential applications in biomedicine and biotechnology. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(1): 50–52 [译自: 中山大学学报 (自然科学版)]     

Synthesis and thermosensitive behavior of dextran graft copolymers containing poly (N-vinylcaprolactam) side chains

New graft copolymers were synthesized by grafting N-vinylcaprolactam onto dextran. Their composition and structure were investigated by elemental analyses, infrared spectra and thermogravimetric analyses. By optical transmittance measurements, it was found that the aqueous solutions of these graft copolymers showed a temperature-dependent transmittance change due to the introduction of thermosensitive poly (N-vinylcaprolactam) graft chains. Moreover, the lower critical solution temperature (LCST) of the graft copolymer in aqueous solution was dependent on its grafting extent and concentration. The LCST value was found to increase with the increase of the grafting extent and decrease with the increase of the copolymer concentration. With these stimuli-response properties, such polysaccharide derivative may hold potential applications in biomedicine and biotechnology.     

Synthesis,properties, and gas permeation performance of cardo poly(arylene ether sulfone)s containing phthalimide side groups

Novel bisphenol monomers ( 1a‐d ) containing phthalimide groups were synthesized by the reaction of phenolphthalein with ammonia, methylamine, aniline, and 4‐tert‐butylanilne, respectively. A series of cardo poly(arylene ether sulfone)s was synthesized via aromatic nucleophilic substitution of 1a‐d with dichlorodiphenylsulfone, and characterized in terms of thermal, mechanical and gas transport properties to H₂, O₂, N₂, and CO₂. The polymers showed high glass transition temperature in the range 230–296°C, good solubility in polar solvents as well as excellent thermal stability with 5% weight loss above 410°C. The most permeable membrane studied showed permeability coefficients of 1.78 barrers to O₂ and 13.80 barrers to CO₂, with ideal selectivity factors of 4.24 for O₂/N₂ pair and 28.75 for CO₂/CH₄ pair. Furthermore, the structure–property relationship among these cardo poly(arylene ether sulfone)s had been discussed on solubility, thermal stability, mechanical, and gas permeation properties. The results indicated that introducing 4‐tert‐butylphenyl group improved the gas permeability of polymers evidently. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and properties of poly(phenylene sulfide)s containing carbonyl and sulfonyl groups

With a view to study and compare the properties of poly(phenyienc sulfide)s containing carbonyl and sulfonyl backbone units, 1,4-bis(phenylthio)-benzene, and bis(4-phenylthio)diphenyl sulfone, were prepared and subjected to Fricdel-Crafts type polycondensation with various aromatic diacid chlorides. The resulting polymers had inherent viscosities in the range 0.101—0.141 dl/g. These polymers were not soluble in common organic solvents and exhibited good thermal stabilities.     

Synthesis and characterization of soluble poly(ether imide)s containing fluorenyl cardo groups

Two series of poly(ether imide)s (PEIs) containing fluorenyl cardo groups in the main chains were synthesized, which are derived from the polycondensation of 9,9′‐bis(4‐aminophenoxyphenyl)fluorene (BAOFL) or 9,9′‐bis(3‐trifluoromethyl,4‐aminophenoxyphenyl)fluorene (6F‐BAOFL) with four kinds of dianhydrides (3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalicanhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bisphenol‐A dianhydride), respectively. The PEI films and PEI powder were prepared by thermal and chemical imidization, respectively. The PEIs were characterized by FTIR, ¹H‐NMR, differential scanning calorimetry, thermogravimetric analysis, and UV–vis were performed on inherent viscosity, solubility, and tensile tests. The effects of fluorenyl cardo groups and ether linkages on the solubility, tensile properties, thermal stability, and optical properties were investigated in detail. It was found that the PEIs had good solubility in common organic solvents and good optical transparency in visible light region. In addition, the PEI films exhibited excellent tensile and thermal properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Antiplatelet adhesion behavior of hyperbranched poly(l-lactide)s containing glutamic acid terminal groups

The surface properties and antiplatelet adhesion behavior of terminally functionalized hyperbranched poly(l -lactide)s (HB PLLAn-Glu, n = 5, 10, 20) were examined. Contact angle changes and X-ray photoelectron spectroscopic measurements indicated that the hydrated glutamic acid units in HB PLLAn-Glu films migrated to the surface during immersing in water and unique microdomains were observed from the HB PLLA10-Glu film after water immersion. HB PLLA10-Glu and HB PLLA5-Glu prevented platelet adhesion, but HB PLLA20-Glu showed the typical platelet adhesion response for a hydrophobic surface. Both the high hydrophilicity and microdomain formation of HB PLLAn-Glu contributed to the efficient antiplatelet adhesion behavior. The glutamic acid-terminated HB PLLA10-Glu films were more effective at preventing platelet adhesion than the 2-methoxyethoxy-terminated HB PLLA10 films. This study is the first example of platelet adhesion properties being controlled by the terminal functional groups and branching density of hyperbranched polymers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46910.     

Synthesis and properties of side chain cholesteric liquid‐crystalline polyacrylates containing two mesogenic groups

The synthesis of side chain cholesteric liquid‐crystalline polymers containing both 4‐cholesteryl‐4'‐acryloyloxybenzoate (M_I) and 4‐methoxyphenyl‐4'‐acryloyloxybenzoate (M_II) mesogenic side groups is described. The chemical structures of the obtained monomers and polymers are confirmed by Fourier transform infrared (FTIR) spectroscopy. The phase behavior and optical properties of the synthesized monomers and polymers were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetric analyses (TGA). The homopolymer IP reveals a cholesteric phase and VIIP displays a nematic phase. The copolymers IIP–VIP exhibit, respectively, cholesteric oily‐streak texture and focal‐conic texture. The fixation of the helical pitch and oily‐streak texture of the cholesteric phase is achieved by quenching, and polymer films with different reflection colors are obtained. The experimental results demonstrate that the glass transition temperature (T_g) and the melting temperature (T_m) of the copolymers IIP–VIP decrease, whereas the isotropization temperature (T_i) and the mesomorphic temperature range (ΔT) increase with increasing content of mesogenic M_II units. TGA results indicate that the temperatures at which 5% mass loss occurred (T_5wt%) of all copolymers are >245°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1936–1941, 2003     

Monotropic liquid crystalline poly(β-thioester)s containing bis (p-oxybenzoate) mesogenic units

Summary A new series of thermotropic liquid crystalline poly(-thioester)s was prepared by a Michael-type polyaddition of ,-polymethylenedithiols of different length to a mesogenic diacrylate containing two bis(p-oxybenzoate) units symmetrically connected through a dodecamethylene segment. The thermotropic behaviour was studied by combined DSC and thermal-optical analyses. All the poly(-thioester)s investigated exhibited quite unusual monotropic mesomorphism.     

New aromatic poly(ether-ketone)s containing hexafluoroisopropylidene groups

Summary New aromatic poly(ether-ketone)s containing hexafluoroisopropylidene groups have been prepared by aromatic nucleophylic displacement reaction of the potassium salts of aromatic dihydroxy compounds containing fluoren, 1,3,4-oxadiazole or phenylquinoxaline rings with 2,2-bis[4-(4-fluorobenzoylphenyl)hexafluoropropane. These polymers were readily soluble in various organic solvents such as N,N-dimethylformamide, pyridine, tetrahydrofuran and chloroform and gave flexible films by casting such solutions. Their glass transition temperatures (T_g) were in the range of 189–222°C and they were thermally stable up to 480°C. The polymer films displayed low dielectric constants, in the range of 2.8 – 3.2, and good mecanical properties, with tensile strength in the range of 46 – 61 MPa and elastic modulus of 1.4 – 1.6 GPa. Received: 6 April 2001/Revised version: 31 July 2001/Accepted: 31 July 2001     

丙烯酸乙酯改性硅油的合成和性能研究

以含氢硅油(PHMS)和丙烯酸乙酯(EA)为原料,制得兼有二者性能的丙烯酸乙酯改性硅油。研究了PHMS含氢量和粘度对产品性能的影响,并用二元回归分析法进一步分析了PHMS含氢量和粘度与产品性能的关系。结果表明,PHMS含氢量对产品性能影响比其粘度显著,且PHMS含氢量和粘度越小,产品的性能越佳,其粘温系数为0.61,表面张力为21.2 mN/m。且二元回归方程分别预测了产品的粘度指数、粘温系数和表面张力,误差绝对值分别控制在7.411 8,0.009 1和0.095 3 mN/m内。     

Synthesis and characterization of liquid crystalline copolysiloxanes containing azobenzene dyes and 1,3-dioxane based mesogenic side groups

Summary The synthesis and characterization of nine side-chain liquid crystalline copolysiloxanes containing trans-5-(n-undecanyl)-2-(4-cyanophenyl)-1,3-dioxane and 4-(alkanyloxyphenylazo)benzonitrile side groups are presented. The azobenzene dye contents in the copolymers range from about 5 to 20 wt.-%. The nature of the mesophase exhibited by the copolysiloxanes depends very much on the dye concentration. Three copolysiloxanes which contain about 5 wt.-% azobenzene dye, display a smectic A phase while the other six copolysiloxanes which contain more then 10 wt.-% azobenzene dye, exhibit a nematic phase. All the obtained copolysiloxanes show a very low glass transition temperature and a very wide temperature range of mesophase.     

Synthesis and characterization of novel aromatic poly(ester amide)s containing pendant trifluoromethylphenoxy groups

A new diamine monomer, 1,4-bis(4-aminophenoxycarbonyl)-2-(4-trifluoromethylphenoxy)benzene containing the trifluoromethyl and ester groups, was prepared from 2-(4-trifluoromethylphenoxy)terephthalyol chloride and 4-nitrophenol in two steps. Then, a series of novel aromatic poly(ester amide)s containing pendant trifluoromethylphenoxy groups with inherent viscosities of 0.51–1.14 dL/g have been prepared by low-temperature solution polycondensation from this diamine with various aromatic diacid chlorides. All the poly(ester amide)s are amorphous and readily soluble in many organic solvents such as N,N-dimethylacetamide (DMAC) and dimethyl sulfoxide. Tough and flexible polymer films cast from DMAc solutions have tensile strengths of 89–114 MPa, elongations at break of 5.8–8.8%, and initial moduli of 2.2–3.2 GPa. These poly(ester amide)s show glass transition temperatures between 166 and 256°C, 10% weight loss temperatures ranging from 395 to 445°C, and char yields higher of 46–56% at 800°C in nitrogen, and also exhibit low dielectric constants ranging from 3.31 to 3.52 (1 MHz), and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 362–380 nm range. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and study of new poly(ester‐imide)s containing triptycene groups

A new triptycene‐containing dicarboxylic acid monomer was successfully synthesized by refluxing the diamine, bis(4‐aminophenoxy)phenyl triptycene with trimellitic anhydride in glacial acetic anhydride. A series of novel thermally stable poly(ester‐imide)s were prepared from dicarboxylic acid, bis(4‐trimellitimido phenoxy)phenyl triptycene with various diols by the direct polycondensation. The polymers were obtained in quantitative yields with inherent viscosities of 0.27–0.74 dL g^?1. The resulting polymers dissolved in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, and pyridine. These polymers were fairly stable up to a temperature >450°C and lost 10% weight in the range of 477°C and 575°C in nitrogen. The UV–V is absorption spectra revealed that most of the polymers had absorption maxima around 310 and 341 nm. POLYM. ENG. SCI., 54:2252–2257, 2014. © 2013 Society of Plastics Engineers     

Photoinduced orientation of liquid crystalline copolymer films containing 4-oxybenzoic acid side groups and photo-cross-linkable mesogenic side groups

The cooperative molecular reorientation in methacrylate copolymer films with hexamethylene spacer groups terminated with 4-oxybenzoic acid (BA) and 4-(4-methoxycinnamoyloxy)biphenyl (MCB) in their side chains was investigated by irradiating with linearly polarized ultraviolet light (LPUV) and subsequent annealing. A high degree of cooperative in-plane reorientation of both the BA and MCB groups was obtained when the composition of the BA groups was greater than 50 mol% and hydrogen (H)-bonded LC mesogenic dimers of BA molecules existed. On the other hand, the molecular reorientation was restricted when the BA groups did not form H-bonds. It was clarified that the amount of axis-selectively photoreacted MCB groups and the H-bonds of the BA groups that exhibit a LC nature play important roles in the thermally enhanced molecular reorientation.     

Poly(dithiafulvene)s containing alkoxy groups and mesogenic moiety in the side chain: synthesis,properties and their charge-transfer complex

Summary Poly(dithiafulvene)s having alkoxy group and mesogenic moiety in the side chain were prepared by cycloaddition polymerization. The effects of the side chains on the structural and optical properties of poly(dithiafulvene)s in solution were investigated. Furthermore, the film state properties of the polymers and their charge transfer complex with electron acceptor were studied before and after annealing.     

丙烯酸丁酯改性硅油的合成与性能

以丙烯酸丁酯(BA)和含氢硅油(PHMS)为原料,制得了兼有二者性能的丙烯酸丁酯改性硅油.用FT-IR和1H-NMR表征了聚合物的结构.用回归分析方法研究了聚合物黏温性能、表面性能与PHMS含氢质量分数和黏度的关系.结果表明:PHMS的含氢质量分数对聚合物性能影响比其黏度的影响显著,且PHMS含氢质量分数和黏度越小,聚合物的性能越佳;在PHMS含氢质量分数为0.130%,黏度为15.5 mm2/s时,产物的黏度指数(VI)为414,黏温系数(VTC)为0.61,表面张力(ST)为22.0 mN/m;二元回归方程有效地预测了聚合物的VI、VTC和ST的值.