Preparation and surface properties of the polysiloxane material modified with fluorocarbon side chains

The novel polysiloxane material modified with fluorocarbon side chains was synthesized. FTIR, FNMR were used to characterize the copolymer structure. The emulsion of the modified polysiloxane was prepared. The reflectance spectrum of the dyed polyester fabric treated with the polymer was also discussed. The effect of the modified polysiloxane on the color fastness of the dyed polyester fabric was investigated. The results show that the novel polysiloxane material modified with fluorocarbon side chains had excellent surface activity. It did not affect the shade of color and the fastnesses of the dyed fabrics and could improve the handle of fabrics. The treated fabric with the modified polysiloxane showed excellent repellency to water.     

New side chain liquid crystalline polymers: synthesis and thermal properties of side chain polyacrylates having segmented spacers

In order to acquire high mobility of a mesogenic group, we propose a new type of side chain liquid crystal polymer having segmented spacers, consisting of binary moieties of an oligo(ethylene oxide) segment and analkylene segment. Six kinds of polyacrylates having segmented spacers consisting of different lengths of an oligo(ethylene oxide) and an alkylene, and having 4'-cyanobiphenyl as a mesogenic group have been synthesized, and their thermal properties investigated. Some of these polyacrylates exhibit a mesophase and show an extremely low glass transition temperature compared with LC polyacrylates having ordinary alkylene spacers.     

New side chain liquid crystalline polymers: synthesis and thermal properties of side chain polyacrylates having segmented spacers

In order to acquire high mobility of a mesogenic group, we propose a new type of side chain liquid crystal polymer having segmented spacers, consisting of binary moieties of an oligo(ethylene oxide) segment and analkylene segment. Six kinds of polyacrylates having segmented spacers consisting of different lengths of an oligo(ethylene oxide) and an alkylene, and having 4'-cyanobiphenyl as a mesogenic group have been synthesized, and their thermal properties investigated. Some of these polyacrylates exhibit a mesophase and show an extremely low glass transition temperature compared with LC polyacrylates having ordinary alkylene spacers.     

长链烷氧甲基冠醚的合成及表面活性

本文研究了通过长链烷氧甲基取代三甘醇(2)的环化反应合成一系列长链烷氧甲基-15-冠-5 (3) .在25℃, 35℃,45℃下测定了烷氧甲基冠醚化合物和(2)的表面张力,CMC及γ~C~M~C.结果显示,随着疏水链碳原子数的增加,CMC值减小,疏水链的碳原子数大于8的两亲分子在水溶液中可形成胶束.     

Organic–inorganic polyurethanes with double decker silsesquioxanes in the main chains: Morphologies,surface hydrophobicity,and shape memory properties

In this contribution, we reported an investigation of the morphologies, surface hydrophobicity, and shape memory properties of the organic–inorganic polyurethanes with double decker silsesquioxane (DDSQ) in the main chains. It was found that the organic–inorganic polyurethanes were microphase‐separated and that the POSS cages in the main chains were self‐organized into the spherical microdomains with the size of 10–50 nm in diameter. The introduction of POSS cages into the main chains resulted in the enhancement of glass transition temperatures (T_g's). In the meantime, the surface dewettability of the materials was significantly enhanced. X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) indicates the improvement of the surface hydrophobicity resulted from the enrichment of POSS at the surfaces of the polyurethanes. The mechanical analyses, such as dynamic mechanical analysis (DMA) and creep‐recovery analysis (CRA), indicate that the POSS microdomains dispersed in the polyurethanes behaved as the physical crosslinking sites and promoted the formation of the crosslinked networks. Owing to the introduction of DDSQ into the main chains, the organic–inorganic polyurethanes significantly displayed shape memory properties, in marked contrast to the unmodified and linear polyurethane. The shape memory behavior has been addressed on the formation of the strong physically crosslinked networks in the organic–inorganic polyurethanes. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 893–906     

Surface-active properties of new cationic gemini surfactants with cyclic spacer

Three cationic gemini surface active compounds of the type (1r,4r)-1,4-dialkyl-1,4-dimethy-l-piperazine-1,4-diium bromide (Ia, Ib, and Ic), were synthesized. They were characterized using elemental analysis and ¹H-NMR spectra. Their surface-active properties were measured in aqueous solutions with different concentrations at different temperatures (25, 40, and 55°C). Various surface measurements of these gemini surfactants, (compared to the conventional one, 1-Dodecyl-1-methylpiperidinium bromide (a)) were estimated, specifically critical micelle concentration (CMC), effectiveness (π_CMC), efficiency (P_C20) as well as maximum surface excess (Γ_max) and minimum surface area (A_min). The measurements of the gemini compounds gave low CMC, high efficiency in reducing the surface tension, and intense adsorption at air/water interface. These surfactants have lower Krafft points and thus better solubility. Thermodynamic data, free energy, entropy, and enthalpy changes (ΔG°, ΔS°, and ΔH°) for micellization at the air/water interface and also for adsorption in the bulk of surface-active solutions were calculated.     

Amphiphilic silica/fluoropolymer nanoparticles: Synthesis,tem‐responsive and surface properties as protein‐resistance coatings

A series of amphiphilic silica/fluoropolymer nanoparticles of SiO₂‐g‐P(PEGMA)‐b‐P(12FMA) were prepared by silica surface‐initiating atom transfer radical polymerization (SI‐ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and poly dodecafluoroheptyl methacrylate (P12FMA). Their amphiphilic behavior, lower critical solution temperature (LCST), and surface properties as protein‐resistance coatings were characterized. The introduction of hydrophobic P(12FMA) block leads SiO₂‐g‐P(PEGMA)‐b‐P(12FMA) to form individual spherical nanoparticles (～150 nm in water and ～170 nm in THF solution) as P(PEGMA)‐b‐P(12FMA) shell grafted on SiO₂ core (～130 nm), to gain obvious lower LCST at 36–52 °C and higher thermostability at 290–320 °C than SiO₂‐g‐P(PEGMA) (LCST = 78–90 °C, T_d = 220 °C). The water‐casted SiO₂‐g‐P(PEGMA)‐b‐P(12FMA) films obtain much rougher surface (125.3–178.4 nm) than THF‐casted films (11.5–16.9 nm) and all SiO₂‐g‐P(PEGMA) films (26.8–31.3 nm). Therefore, the water‐casted surfaces exhibit obvious higher water adsorption amount (Δf = ?494 ～ ?426 Hz) and harder adsorbed layer (viscoelasticity of ΔD/Δf = ?0.28 ～ ?0.36 × 10^?6/Hz) than SiO₂‐g‐P(PEGMA) films, but present loser adsorbed layer than THF‐casted films (ΔD/Δf = ?0.29 ～ ?0.63 × 10^?6/Hz). While, the introduction of P(12FMA) segments does not show obviously reduce in the protein‐repelling adsorption of SiO₂‐g‐P(PEGMA)‐b‐P(12FMA) films (△f = ?15.7 ～ ?22.3 Hz) compared with SiO₂‐g‐P(PEGMA) films (△f = ?8.3 ～ ?11.3 Hz) and no obvious influence on water adsorption of ancient stone. Therefore, SiO₂‐g‐P(PEGMA)‐b‐P(12FMA) is suggested to be used as protein‐resistance coatings. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 381–393     

The POSS side chain epoxy nanocomposite: Synthesis and thermal properties

The IPI‐POSS‐modified epoxy resin (IPEP) was prepared from isocyanato‐propyldinethylsilyl‐isobutyl‐POSS (IPI‐POSS) and diglycidyl ether of bisphenol A epoxy resin. The steric hindrance of the IPEP bulky POSS side chain improved the curing activation energies. The POSS particles sizes were about 2–3 nm and dispersed uniformly. At lower IPEP concentration (POSS < 12 wt %), the glass transition temperatures (T_gs) of the IPEP nanocomposites increased from 118 to 170 °C. The char yield increased from 15 to 20 wt %, and the LOI values increased from 22 to 28. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 643–652, 2010     

Synthesis and photovoltaic properties of fluorene-based copolymers with narrow band-gap units on the side chain

A series of novel polyfluorene copolymers are developed by covalently attaching narrow band gap aryl-heterocycle units of Th-BT-TPA to the side chain of polyfluorene with an alkyl phenyl spacer through Pd-catalyzed Suzuki coupling reactions. The resulting copolymers are soluble in common organic solvents. The electrochemical, optical, and photovoltaic properties of the copolymers are studied. Electrochemical and optical analysis reveal that these polymers exhibit relatively low band gaps from 1.95 to 2.00 eV and exhibit strong absorption in the 300-620 nm region. BHJ solar cells blending copolymers PF-MR15-DBT35 with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) (1:1 weight ratio) as the active layer present a high open-circuit voltage (V_oc∼1.0 V) and a power conversion efficiency of 0.7% under simulated solar light AM1.5G (80 mW/cm²). Further investigations of other polyfluorene copolymers with narrow band gap aryl-heterocycle units on the side chain are in progress.     

Synthesis,properties, and molecular simulations of high-barrier polyimide containing carbazole moiety and amide group in the main chain

An intrinsic high-barrier polyimide (2,7-CPAPPI) containing rigid planar carbazole moiety and amide group in main chain was prepared. The 2,7-CPAPPI shows very attractive barrier performances, possessing water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) low to 0.04 g m⁻² day⁻¹ and 0.11 cm³ m⁻² day⁻¹, respectively. Meanwhile, 2,7-CPAPPI also displays exceptional thermal stability with a glass transition temperature (T_g) of 552°C and coefficient of thermal expansion (CTE) of 15.48 ppm/K. The barrier performances of 2,7-CPAPPI are compared with those of a structural analog (2,7-CPPI, containing only carbazole moiety in the main chain) and a typical polyimide (Kapton). The structure–barrier performances relationship was investigated by molecular simulations, wide angle X-ray diffraction (WAXD), and positron annihilation lifetime spectroscopy (PALS). The results show that 2,7-CPAPPI has more number of intermolecular hydrogen bonds among the three PIs, which leads to close chain packing and thereby high crystallinity, low free volume, and poor chains mobility. That is, the high crystallinity and low free volume of 2,7-CPAPPI decrease the diffusion and solubility of gases. Meanwhile, the poor chains mobility further reduces the gases diffusion. The decreased diffusion and solubility of gases consequently promote the improvement of barrier properties for 2,7-CPAPPI.     

Novel,well‐defined polystyrene with a fluorine cluster end‐capped group: Synthesis,characterization, and surface properties

Novel, well‐defined fluorinated polystyrene was synthesized for the first time via the controlled radical polymerization of styrene through a relatively simple process and was characterized with ¹H NMR, ¹⁹F NMR, and gel permeation chromatography. The surface properties of polystyrene and poly(acrylonitrile‐co‐butadiene‐co‐styrene) films were modified with the obtained polymers. X‐ray photoelectron spectroscopy measurements of the air‐side surface composition of the modified poly(acrylonitrile‐co‐butadiene‐co‐styrene) films showed that fluorine enriched the outermost surface, resulting in fantastic surface properties that came close to those of poly(tetrafluoroethylene). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3853–3858, 2006     

Polyimides with side groups: Synthesis and effects of side groups on their properties

Polyimides are a class of well-known high-performance polymers combined the excellent mechanical, electrical, and thermal properties and widely applied in many high-tech fields. Traditional polyimides can only be processed in the state of soluble intermediates with a hazardous step of cyclodehydration and elimination of a nonvolatile polar solvent. Therefore, a great effort has been devoted to the development of soluble polyimides that can be processed in the full imidation state. The incorporation of side groups into the polyimide backbone is an efficient approach to resolve above problems with a little sacrifice of its inherent merits. The subtle variation of side groups in polyimide backbones has allowed researchers to tune their final properties. In particular, some special side groups can endow polyimides the specific property or functionality to broaden their application fields. In this article, we summarize the synthesis of polyimides with side groups in recent 20 years and further discuss the effect of side groups on their physical and specific properties. The future research directions of polyimides with side groups are also discussed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 533–559     

Fluorinated comblike homopolymers: The effect of spacer lengths on surface properties

A series of polyacrylate monomers with F‐alkylalkyl [F(CF₂)_n(CH₂)_n′] side groups were prepared by free‐radical polymerization. The effect of the chemical structure on the surface properties of poly(ethylene terephthalate)s was evaluated by variations in the relative length of the fluorocarbon and hydrocarbon units in the side group. The resulting polymers were quite surface‐active in the solid state. The surface and bulk organization was investigated by X‐ray photoelectron spectroscopy analysis. A strong correlation between the bulk organization and surface properties of the polymers was established. The outmost layer, formed from trifluoromethyl groups and some ester functions, suggests that the side chain is arranged irregularly in the polymer–air interface. The length of the lateral chain governs this organization: long fluorinated chains and short hydrocarbon spacers are essential elements of the molecular design for such low‐surface‐energy materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3737–3747, 2005     

不等链长的碳氟、碳氢正负离子表面活性剂混合体系的表面活性

研究了全氟辛酸钠与溴化十四烷基三甲铵混合水溶液的表面活性. 测定了不同比例混合物水溶液的表面张力-浓度曲线, 得出临界胶团浓度(cmc)及监 界胶团浓度时的溶液表面张力(γcmc)值. 应用Gibbs吸附公式及吸附层中两表面活性剂分子相互作用参数法求出表面总吸附量、吸附层组成及两表面活性剂分别吸附量等. 指示此吸附层具有多分子层性质. 这可能是碳氢、碳氟正负离子混合体系的特点.     

Effect of carbon fiber surface treatments on the flexural strength and tribological properties of short carbon fiber/polyimide composites

Pitch‐based short carbon fibers (CFs) were treated by air oxidation and cryogenic nitrogen, respectively. Thereafter the treated and untreated CFs were incorporated into polyimide (PI) matrix to form composites. The CFs before and after treatment were examined by XPS and SEM.The flexural strength of the specimen was determined in a three‐point test machine and the tribological properties of PI composites sliding against GCr15 steel rings were evaluated on an M‐2000 model ring‐on‐block test rig. The results show that the surface of the treated CFs became rougher. Lots of active groups formed on the CF surface after air oxidation.The treatment can effectively improve the mechanical and tribological properties in their PI composites due to the enhanced fiber‐matrix interfacial bonding. Copyright © 2008 John Wiley & Sons, Ltd.     

Analyzing the surface properties of acrylic-based water-soluble polymers

The surface properties of newly synthesized N-methoxy isopropyl acrylamide, N-methoxy isopropyl methacrylamide, cyclo propyl acrylamide, and cyclo propyl methacrylamide polymers were investigated using inverse gas chromatography. The highest dispersive component of the surface energy value was obtained for cyclo propyl methacrylamide at 30°C. The values obtained for all polymers were decreasing with the increasing temperature. The values obtained for the acidic and the basic parameters revealed strong basic characters for the surface of N-methoxy isopropyl methacrylamide and cyclo propyl methacrylamide polymers and weak basic characters for the surface of N-methoxy isopropyl acrylamide and cyclo propyl acrylamide polymers.     

Preparation and alignment properties of photosensitive polyimide containing benzophenone in main chain

ABSTRACT

In order to study the effect of benzophenone (BP) group in the main chain on the photo-alignment behaviour of cinnamoyl groups, a novel photosensitive polyimide (BTDA-PI-CA) is synthesised by 3,3?,4,4?-benzophenonetetracarboxylic dianhydride (BTDA), 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (AHHFP) and cinnamoyl chloride. The BTDA-PI-CA films exhibit good alignment performance after the non-polarised ultraviolet ageing lamp exposure, which is due to the polyimide with BP group can be used to improve the photosensitivity. Moreover, the thermal stability of the LC cells is pretty good and the pretilt angle of the LC cells is 0.5, which can be used in parallel mode LCD.     

Structure and properties of a photosensitive polyimide: Effect of photosensitive group

The photosensitive poly(p-phenylene biphenylteracarboximide) (BPDA-PDA) precursor was synthesized by attaching photocross-linkable 2-(dimethylamino)ethyl methacrylate (DMAEM) monomer to its poly(amic acid) through acid/base complexation. The polyimide thin films were prepared by a conventional cast/softbake/thermal imidization process from the photosensitive precursors with various concentrations of DMAEM. The structure and properties of the polyimide films were investigated by small-angle and wide-angle x-ray scattering, refractive indices and birefringence analysis, residual stress and relaxation analysis, stress-strain analysis, and dynamic mechanical thermal analysis. In comparison with the polyimide film from the poly(amic acid), the films, which were imidized from the photosensitive precursors, exhibited a better molecular order and microstructure; however, they exhibited less molecular orientation in the film plane. Despite the enhancement in both the molecular order and microstructure, the film properties (i.e., mechanical properties, thermal expansion, residual stress, optical properties, dielectric constant, and water sorption) degraded overall due to both the decrease in molecular in-plane orientation and the formation of microvoids caused by the bulky photosensitive group during thermal imidization. That is, on one hand, the PSPI precursor formation provides an advantageous, direct patternability to the BPDA-PDA precursor, and on the other hand, it results in degraded properties to the resulting polyimide film. © 1995 John Wiley & Sons, Inc.     

Homologous series of dendronized polymethacrylates with a methyleneoxycarbonyl spacer between the backbone and dendritic side chain: synthesis, characterization, and some bulk properties

First through fourth generation (G1-G4) dendronized macromonomers, 3, 5, 7, and 9, with a methyleneoxycarbonyl spacer between the polymerizable group and dendritic side chain (dendron) were synthesized, and their polymerization behavior to the corresponding dendronized polymers PG1s, PG2s, PG3s, and PG4s, respectively, was investigated by heating the monomers to 55 degrees C without intentional addition of initiator. This self-induced polymerization is referred to as thermally induced radical polymerization (TRP). The molar masses of PG1s-PG4s were determined by gel permeation chromatography in DMF calibrated to a recently developed G1 dendronized polymer standard (PG1). A comparison of this homologous series' polymerization results with those of an already existing one, which differed only by the lack of this spacer (referred to as PG1-PG4), was made to contribute to the issue of whether short spacers have an effect on polymerization. Several representatives of both series were also used in the first systematic and generation-dependent investigation of these unusual comb polymers' bulk properties. Both structure and dynamics were investigated by DSC, X-ray diffraction, and dynamic mechanical measurements.