Synthesis and properties of poly(imide siloxane) block copolymers with different block lengths

Several poly(imide siloxane) block copolymers with the same bis(γ‐aminopropyl)polydimethylsiloxane (APPS) content were prepared. The polyimide hard block was composed of 4,4′‐oxydianiline and 3,3′,4,4′‐diphenylthioether dianhydride (TDPA), and the polysiloxane soft block was composed of APPS and TDPA. The length of polysiloxane soft block increased simultaneously with increasing the length of polyimide hard block. For better understanding the structure–property relations, the corresponding randomly segmented poly(imide siloxane) copolymer was also prepared. These copolymers were characterized by FT‐IR, ¹H‐NMR, dynamic mechanical thermal analysis, thermogravimetric analysis, polarized optical microscope, rheology and tensile test. Two glass transition temperatures (T_g) were found in the randomly segmented copolymer, while three T_gs were found in the block copolymers. In addition, the T_gs, storage modulus, tensile modulus, solubility, elastic recovery, surface morphology and complex viscosity of the copolymers varied regularly with increasing the lengths of both blocks. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Formation of honeycomb‐patterned microporous films based on a fluorinated poly(siloxane imide) segmented copolymer

The preparation of honeycomb‐patterned microporous films from a soluble fluorinated poly(siloxane imide) segmented copolymer (PSI) by means of water‐droplet templating is reported first in this article. The fluorinated PSI was synthesized from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, and diamine‐terminated poly(dimethyl siloxane) by condensation polymerization. The obtained copolymer had good solubility in chlorinated solvents (chloroform, dichloromethane, and 1,2‐dichloroethane), good thermal stability, and a microphase‐separated amorphous structure. The effects of the copolymer concentration, atmospheric humidity, and solvent properties on the pattern formation were investigated. The results show that the film fabricated from the copolymer solution with chloroform as the solvent at a humidity of 90% and a concentration of 0.5 g/L had the most regular honeycomb‐patterned micropores. We could tailor the pore shape and size by changing the copolymer concentration or the atmospheric humidity. The prepared regular honeycomb‐patterned microporous PSI films have potential applications in cell culture and tissue engineering. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and Characteristics of Novel Poly(Imide Siloxane) Segmented Copolymers

New poly(imide siloxane) copolymers for possible use as tough environmentally stable structural matrix resins and structure adhesives have been prepared. Thus, 3,3'-4,4'-benzophenone tertracarboxylic dianhydride was reacted with various Mn aminopropyl-terminated polydimethylsiloxane oligomers and a meta-substituted diamine “chain-extender” such as 3,3'-diaminodiphenyl sulfone or 3,3'-diaminobenzophenone to produce the siloxane-modified poly(amic acid). Thin films were cast from the reaction mixtures and subsequent thermal dehydration produced the poly(imide siloxane) block or segmented copolymers. Upper “cure” temperatures of 300°C were used to insure complete imidization. By varying the amount and molecular weight of the siloxane oligomer, a variety of novel copolymers of controlled composition have been synthesized. Tough, transparent, flexible soluble films were produced by this method. The thermal and bulk properties of films having low to moderate siloxane content closely resemble those of the unmodified polyimide controls. However, toughness and surface behavior can be enhanced.     

Synthesis,characterization, and comparison of properties of novel fluorinated poly(imide siloxane) copolymers

Four new poly(imide siloxane) copolymers were prepared by a one‐pot solution imidization method at a reaction temperature of 180°C in ortho‐dichlorobenzene as a solvent. The polymers were made through the reaction of o‐diphthaleic anhydride with four different diamines—4,4′‐bis(p‐aminophenoxy‐3,3″‐trifluoromethyl) terphenyl, 4,4′‐bis(3″‐trifluoromethyl‐p‐aminobiphenyl ether)biphenyl, 2,6‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)pyridine, and 2,5‐bis(3′‐trifluoromethyl‐p‐aminobiphenylether)thiopene—and aminopropyl‐terminated poly dimethylsiloxane as a comonomer. The polymers were named 1a , 1b , 1c , and 1d , respectively. The synthesized polymers showed good solubility in different organic solvents. The resulting polymers were well characterized with gel permeation chromatography, IR, and NMR techniques. ¹H‐NMR indicated that the siloxane loading was about 36%, although 40 wt % was attempted. ²⁹Si‐NMR confirmed that the low siloxane incorporation was due to a disproportionation reaction of the siloxane chain that resulted in a lowering of the siloxane block length. The films of these polymers showed low water absorption of 0.02% and a low dielectric constant of 2.38 at 1 MHz. These polyimides showed good thermal stability with decomposition temperatures (5% weight loss) up to 460°C in nitrogen. Transparent, thin films of these poly(imide siloxane)s exhibited tensile strengths up to 30 MPa and elongations at break up to 103%, which depended on the structure of the repeating unit. The rheological properties showed ease of processability for these polymers with no change in the melt viscosity with the temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Melt‐intercalation nanocomposites with fluorinated polymers and a correlation for nanocomposite formation

Various fluorinated polymers were investigated to produce polymer nanocomposites with special clays. Natural and organically treated montmorillonite clays were melt‐compounded with the polymers. Characterization by wide‐angle X‐ray scattering and transmission electron microscopy showed the separation of montmorillonite layers and the formation of polymer nanocomposites. Organically treated montmorillonite clay dispersed in poly(vinylidene fluoride) and various vinylidene fluoride copolymers and formed nanocomposites. Natural and organophilic clays were not well dispersed in other fluorinated copolymers and polyethylene. A correlation was developed for the formation of polymer–clay nanocomposite structures in chlorinated and fluorinated polymers in terms of the dielectric constant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1061–1071, 2004     

Synthesis and characterization of poly(dimethyl siloxane) containing poly(vinyl pyrrolidinone) block copolymers

ABA‐type block copolymers containing segments of poly(dimethyl siloxane) and poly(vinyl pyrrolidinone) were synthesized. Dihydroxyl‐terminated poly(dimethyl siloxane) was reacted with isophorone diisocyanate and then with t‐butyl hydroperoxide to obtain macroinitiators having siloxane units. The peroxidic diradical macroinitiators were used to polymerize vinyl pyrrolidinone monomer to synthesize ABA‐type block copolymers. By use of physicochemical methods, the structure was confirmed, and its characterization was accomplished. Mechanical and thermal characterizations of copolymers were made by stress–strain tests and differential scanning calorimetric measurements. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1915–1922, 1999     

Pervaporation membranes based on imide‐containing poly(amic acid) and poly(phenylene oxide)

Three imide‐containing poly(amic acids) were synthesized and used for homogeneous and composite membrane preparation. The transport properties of composite membranes consisting of an imide‐containing poly(amic acid) top layer on an asymmetric porous poly(phenylene oxide) support were studied in the pervaporation of aqueous solutions of organic liquids (ethanol, isopropanol, acetone, and ethylacetate) and organic/organic mixtures (ethylacetate/ethanol, methanol/cyclohexane). For most of the aqueous/organic mixtures, the composite membranes exhibited dehydration properties. Dilute aqueous solutions of ethylacetate were an exception. In these solutions, the composite membranes exhibited organophilic properties, high permeability, and selectivity with respect to ethylacetate. In the pervaporation of methanol/cyclohexane mixtures, methanol was removed with very high selectivity. To account for specific features of pervaporation on the composite membranes, the sorption and transport properties of homogeneous membranes prepared from polymers comprising the composite membrane [imide‐containing poly(amic acids) and poly(phenylene oxide)] were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2361–2368, 2003     

Preparation and properties of poly(methyltrifluoropropylsiloxane‐b‐imide) copolymer. I

Poly(methyltrifluoropropylsiloxane‐block‐imide) copolymers (PSBPI), containing various contents of fluorosiloxane, were prepared by the thermal imidization of 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), 4,4′‐oxydianiline (ODA), and α,ω‐aminopropyl‐terminated poly(methyltrifluoropropylsiloxane) prepolymer (APMFS). APMFS was prepared from an equilibrium polymerization of (3,3,3‐trifluoropropyl)methylcyclotrisiloxane (D₃^{Me,CH2,CH2,CF3}) with 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane in the presence of the tetramethylammoniumhydroxide (TMAH) catalyst. The content of APMFS, in the reaction mixture, was varied from 0 to 30 wt % of diamine. The structure of copolymer was confirmed by FTIR spectroscopy. The thermal stability, linear coefficient of thermal expansion, modulus, X‐ray pattern, and other properties, such as surface enrichment behavior and solubility, were investigated. PSBPI exhibited relatively low crystallinity regardless of the APMFS content in the copolymer. On the other hand, thermogravimetric, thermomechanical, dynamic mechanical, and surface properties were affected by the content of APMFS segment in the copolymer backbone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2867–2874, 2002     

Shear‐induced migration of nanoclay during morphology evolution of PBT/PS blend

Three different poly(imide-siloxane)s (PIS) containing rigid imide groups were synthesized by the reaction of amine end-capped imides to the siloxane backbone. These highly soluble amine terminated imides were synthesized by reacting fluorinated anhydride and three different amines (DDBP, DDM, DBP). The imides were grafted to the siloxane backbone by the epoxy group cleavage. All the polymers were obtained in quantitative yields with the inherent viscosities ranging from 0.32 to 0.45 dL/g. The polymers were characterized by FTIR, ¹H and ¹³C NMR, and their thermal properties were studied. The DSC results showed two distinct glass transition temperatures demonstrating the existence of phase separation between the hard imide and soft siloxane groups. Polymeric membranes were prepared employing the coupling reaction between PIS and the polydimethylsiloxane matrix by varying the amount of incorporation of PIS. The membranes showed a high tensile strength of 82 MPa. The contribution of polar and dispersion component towards the total surface energy was studied by the contact angle measurements, and a reduction in surface tension of 15 mN/m was achieved with the fluorine containing PIS membrane. The study of the surface morphology was studied which confirmed the existence of phase separation in these systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,morphology and properties of poly(dimethylsiloxane)/poly(n-butyl acrylate) mixed soft block-based copolymers: A new class of thermoplastic elastomer

Design, synthesis, morphology, mechanical properties and in vitro oxidative stability of new class of surface modified thermoplastic elastomers containing mixed soft rubbery poly(n-butyl acrylate-b-dimethylsiloxane-b-n-butyl acrylate) (PnBA-b-PDMS-b-PnBA) block and glassy poly methyl methacrylate (PMMA) end blocks have been reported. Thus well-defined pentablock copolymers such as PMMA-b-PnBA-b-PDMS-b-PnBA-b-PMMA were synthesized by Atom Transfer Radical Polymerization (ATRP). Moderate amount of PDMS (8–15 wt%) in the copolymers significantly enhances the oxidative stability of the surface and contact angle of water in compare to neat PMMA-b-PnBA-b-PMMA copolymer. The phase morphology of such type of copolymers was studied in detailed which suggests that the mixed soft PnBA-b-PDMS-b-PnBA part forms single phase and the degree of phase separation between PnBA-b-PDMS-b-PnBA and PMMA in PMMA-b-PnBA-b-PDMS-b-PnBA-b-PMMA copolymer is higher than the degree of phase separation between PnBA and PMMA in PnBA-b-PDMS-b-PnBA copolymer. This approach of surface modification was extended to synthesize PMMA-b-PLMA-b-PDMS-b-PLMA-b-PMMA (PLMA = polylauryl methacrylate) block copolymers with improved surface properties.     

Preparation of novel fluorinated block copolyimide membranes for gas separation

We synthesized novel fluorinated block copolyimides with various diamine compositions and block chain lengths by chemical imidization in a two‐pod procedure. We describe the gas‐transport properties of the novel block copolyimide membranes. We demonstrate that the gas‐transport properties of the copolyimide membranes strongly depended on the block chain lengths. The gas permeabilities of the copolyimide membranes increased with increasing block chain length, and the gas selectivities increased with decreasing lengths. We clarify that the gas diffusivity of the block copolyimide membrane dominated the gas‐transport properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2436–2442, 2006     

Preparation and surfactancy of branched copolymers from poly(oxyalkylene)‐amine and trichlorotriazine coupling

A family of branched and block copolymers consisting of poly(oxyalkylene) segments was prepared by using 2,4,6‐trichloro‐1,3,5‐triazine as the amine coupling agent. The copolymers were characterized to have a high molecular weight of up to 22,600 g/mol (Mn) and be thermally stable due to the presence of triazine cores and reactive chloride functionalities. Using the trifunctional poly(oxypropylene)‐block amines as the starting material and a two‐step coupling process, the prepared copolymers are star‐shape or branched, multiple‐block copolymers, with a versatile solubility in water or organic solvents. Further variation in amine structures of hydrophobic poly(oxypropylene) (POP‐) and hydrophilic poly(oxyethylene) (POE‐) blocks may allow the prepared copolymers to be amphiphilic. As an example, the triazine/POP T‐5000/POE ED‐2001 copolymer behaves as a surfactant and exhibits the capability of reducing toluene/water interfacial tension until 1.3 mN/m at critical association concentration as low as 0.001 wt %. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 29–36, 2005     

Thermal and thermo‐oxidative degradation properties of poly(benzimidazole amide imide) copolymers

In this study, 3,3′‐dinitrobenzidine was first reacted with excess isophthaloyl chloride to form a monomer with dicarboxylic acid end groups. Two types of aromatic dianhydride, [viz., pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐sulfonyldiphthalic anhydride (DSDA)] also were reacted with excess 4,4′‐diphenyl‐ methane diisocyanate (MDI) to form polyimide prepolymers terminated with isocyanate groups. The prepolymers were reacted further with the diacid monomer to form a nitro group–containing aromatic poly(amide imide) copolymers. The nitro groups in these copolymers were hydrogenated to form amine groups and cyclized at 180°C to form the poly(benzimidazole amide imide) copolymers in polyphosphoric acid (PPA), which acts as a cyclization agent. From the viscosity measurements, copolymer appeared to be a reasonably high molecular weight. From the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements it was shown that the glass transition temperature of copolymers was in the range of ～270–322°C. The 10% weight loss temperatures were in the range of 460 ～ 541°C in nitrogen and ～441–529°C in air, respectively. The activated energy and the integration parameter of degradation temperature of the copolymers were evaluated with the Doyle‐Ozawa method. It indicated that these copolymers have good thermal and thermo‐oxidative stability with the increase in imide content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2072–2081, 2004     

Factors influencing thermal,mechanical, optical,and adhesive properties of segmented poly(imide siloxane) copolymers films

Poly(imide siloxane), block and blend copolymer, were synthesized using different methods to explore the influence of siloxane chains. The flexible siloxane chains enrichment on surface of copolymer, enhance hydrophobic and adhesive with copper foil. It also improves light transmittance of polyimide film in the visible light region. The effect of different preparation methods on the aggregation in polymers and on polymer properties, especially adhesion and water absorptivity, are also discussed. The imidization temperature and synthesis method (blend and block) during the reaction has a significant effect on the properties of the product, especially thermal properties (T _g values are 207 °C for block and 180 °C for blend) and mechanical properties (elongation of 130% for block and 50% for blend). The bonding strength of polymer films used as hot melt adhesive was also tested. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48148.     

两亲扩展型共聚物的合成及中间极性嵌段对乳化性能的影响

采用聚乙二醇单甲醚(Mn=1 900,5 000)分别引发丙交酯和ε-己内酯开环聚合合成了中间嵌段(PLA)聚合度递增的聚乙二醇-聚丙交酯-聚己内酯(MPEG-PLA-PCL)两亲扩展型共聚物和相应的聚乙二醇-聚己内酯(MPEG-PCL)两嵌段共聚物。用FTIR、1HNMR和GPC对产物结构进行了表征,研究了共聚物和常规低分子表面活性剂的乳化性能,探讨了中间极性嵌段的长度对共聚物乳化性能的影响。结果表明,对于甲苯/水体系,共聚物可用于制备稳定的O/W型乳液,且三嵌段共聚物的乳化性能优于低分子表面活性剂;随着引入PLA嵌段聚合度的增加,共聚物的乳化能力呈先增加后减小的趋势;相对于MPEG1900系列共聚物,MPEG5000系列共聚物中需要引入更长的中间嵌段才能获得最佳乳化性能。     

Synthesis and characterization of graft copolymers of syndiotactic polystyrene with polybutadiene and 4‐methylstyrene

The basic method for synthesizing syndiotactic polystyrene‐g‐polybutadiene graft copolymers was investigated. First, the syndiotactic polystyrene copolymer, poly(styrene‐co‐4‐methylstyrene), was prepared by the copolymerization of styrene and 4‐methylstyrene monomer with a trichloro(pentamethyl cyclopentadienyl) titanium(IV)/modified methylaluminoxane system as a metallocene catalyst at 50°C. Then, the polymerization proceeded in an argon atmosphere at the ambient pressure, and after purification by extraction, the copolymer structure was confirmed with ¹H‐NMR. Lastly, the copolymer was grafted with polybutadiene (a ready‐made commercialized unsaturated elastomer) by anionic grafting reactions with a metallation reagent. In this step, poly(styrene‐co‐4‐methylstyrene) was deprotonated at the methyl group of 4‐methylstyrene by butyl lithium and further reacted with polybutadiene to graft polybutadiene onto the deprotonated methyl of the poly(styrene‐co‐4‐methylstyrene) backbone. After purification of the graft copolymer by Soxhlet extraction, the grafting reaction copolymer structure was confirmed with ¹H‐NMR. These graft copolymers showed high melting temperatures (240–250°C) and were different from normal anionic styrene–butadiene copolymers because of the presence of crystalline syndiotactic polystyrene segments. Usually, highly syndiotactic polystyrene has a glass‐transition temperature of 100°C and behaves like a glassy polymer (possessing brittle mechanical properties) at room temperature. Thus, the graft copolymer can be used as a compatibilizer in syndiotactic polystyrene blends to modify the mechanical properties to compensate for the glassy properties of pure syndiotactic polystyrene at room temperature. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of fluorinated poly(imide–amide–sulfone)s

A series of new, fluorinated poly(imide–amide–sulfone)s has been synthesized by solution polycondensation of aromatic diamines containing sulfone groups with diacid chlorides incorporating both imide and hexafluoroisopropylidene units. These polymers are soluble in polar amidic solvents, and their solutions can be cast into colorless, thin, flexible films having good electrical insulating properties and high thermal stability. The dielectric constant value is 3.49–3.68. The decomposition temperature in air is 464–479°C, and the glass transition temperature is in the range 279–359°C. All these characteristics have been discussed and compared with those of related fluorinated poly(imide–amide)s which do not contain sulfone groups and with other imide polymers without hexafluoroisopropylidene units. © 1995 John Wiley & Sons, Inc.     

Effect of matrix chemical structure on the thermo‐oxidative stability of addition cure poly(imide siloxane) composites

A series of addition cure poly(imide siloxane) resins were synthesized, incorporating various concentrations of α, ω‐bis(3‐aminopropyl) poly(dimethyl‐diphenylsiloxanes), and α, ω‐bis(p‐aminophenyl) poly(dimethylsiloxane) into the formulated imide oligomer. Both carbon and glass fiber textile laminates were fabricated using amic acid and polymerization of monomer reactants (PMR) approaches. The cured composite laminates were subjected to an accelerated thermo‐oxidative aging environment of 400°C for 100 h in air. Physical, thermal, and mechanical properties were evaluated to determine the structure‐oxidative stability interrelationships. In general, composite mechanical properties were found to increase with increasing siloxane concentration in the matrix. Composite thermo‐oxidative durability (measured via mass loss and mechanical property retention after oxidative aging) was improved through incorporation of diphenyl and diphenyl‐dimethyl siloxane segments into the imide oligomer backbone up to ∼35% by weight aminosiloxane. Oxidative stability was found to be mostly dependent on the degree of phenyl substitution on the silicon atoms in the siloxane blocks, as compared to the moiety attaching the amine groups to the siloxane block. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Properties of (BA)n-B type block copolymers of butadiene and dimethyl itaconate prepared using macroazonitrile initiators

Multi-block copolymers of the (BA)_n-B type, where A is poly(dimethyl itaconate) and B is polybutadiene, were synthesised using a macroazonitrile initiator. This was prepared by the reaction of 4, 4′ azobis (4-cyanopentanoyl chloride) with hydroxyl terminated polybutadienes. and subsequent decomposition of the azo group in the presence of dimethyl itaconate monomer yielded the block copolymer. Measurement of their glass transition temperatures revealed that the copolymers formed two phases. The dynamic thermomechanical properties were measured and this demonstrated that in the temperature range 290–400K, the glassy poly(dimethyl itaconate) blocks acted as crosslinking sites for the elastomeric polybutadiene blocks and that the materials behaved like typical elastoplastic block copolymers. Property variation was obtained when the ratio of polybutadiene to poly(dimethyl itaconate) in the copolymers was altered.     

Phosphorus‐containing poly(ester‐imide)–polydimethylsiloxane copolymers

New phosphorus‐containing poly(ester‐imide)‐polydimethylsiloxane copolymers were prepared by solution polycondensation of 1,4‐[2‐(6‐oxido‐6H‐dibenz < c,e > < 1, 2 > oxaphosphorin‐6‐yl)]naphthalene‐bis(trimellitate) dianhydride with a mixture of an aromatic diamine (1,3‐bis(4‐aminophenoxy)benzene) and α,ω‐bis(3‐aminopropyl)oligodimethylsiloxane of controlled molecular weight, in various ratios. Poly(amic acid) intermediates were converted quantitatively to the corresponding polyimide structures using a solution imidization procedure. The polymers are easily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylformamide, as well as in less polar solvents such as tetrahydrofuran. They show good thermal stability, the decomposition temperature being above 370 °C. The glass transition temperatures are in the range 165–216 °C. Solutions of the polymers in N‐methyl‐2‐pyrrolidone exhibit photoluminescence in the blue region. Copyright © 2010 Society of Chemical Industry