Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane‐block‐poly(methyl methacrylate) blends

A polydimethylsiloxane‐block‐poly(methyl methacrylate) (PDMS‐b‐PMMA) diblock copolymer was synthesized by the atom transfer radical polymerization method and blended with a high‐molecular‐weight poly(vinylidene fluoride) (PVDF). In this A‐b‐B/C type of diblock copolymer/homopolymer system, semi‐crystallizable PVDF (C) and PMMA (B) block are miscible due to favorable intermolecular interactions. However, the A block (PDMS) is immiscible with PVDF and therefore generates nanostructured morphology via self‐assembly. Crystallization study reveals that both α and γ crystalline phases of PVDF are present in the blends with up to 30 wt% of PDMS‐b‐PMMA block copolymer. Adding 10 wt% of PVDF to PDMS‐b‐PMMA diblock copolymer leads to worm‐like micelle morphology of PDMS of 10 nm in diameter and tens of nanometers in length. Moreover, morphological results show that PDMS nanostructures are localized in the inter‐fibrillar region of PVDF with the addition of up to 20 wt% of the block copolymer. Increase of PVDF long period by 45% and decrease of degree of crystallization by 34% confirm the localization of PDMS in the PVDF inter‐fibrillar region. © 2018 Society of Chemical Industry     

Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene blends

An approach to achieve confined crystallization of ferroelectric semicrystalline poly(vinylidene fluoride) (PVDF) was investigated. A novel polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene (PDMS‐b‐PMMA‐b‐PS) triblock copolymer was synthesized by the atom‐transfer radical polymerization method and blended with PVDF. Miscibility, crystallization and morphology of the PVDF/PDMS‐b‐PMMA‐b‐PS blends were studied within the whole range of concentration. In this A‐b‐B‐b‐C/D type of triblock copolymer/homopolymer system, crystallizable PVDF (D) and PMMA (B) middle block are miscible because of specific intermolecular interactions while A block (PDMS) and C block (PS) are immiscible with PVDF. Nanostructured morphology is formed via self‐assembly, displaying a variety of phase structures and semicrystalline morphologies. Crystallization at 145 °C reveals that both α and β crystalline phases of PVDF are present in PVDF/PDMS‐b‐PMMA‐b‐PS blends. Incorporation of the triblock copolymer decreases the degree of crystallization and enhances the proportion of β to α phase of semicrystalline PVDF. Introduction of PDMS‐b‐PMMA‐b‐PS triblock copolymer to PVDF makes the crystalline structures compact and confines the crystal size. Moreover, small‐angle X‐ray scattering results indicate that the immiscible PDMS as a soft block and PS as a hard block are localized in PVDF crystalline structures. © 2019 Society of Chemical Industry     

Characteristics of the degradation and improvement of the thermal stability of poly(siloxane urethane) copolymers

This work investigates the characteristics of the thermal degradation of poly(ether urethane) (E‐PU) and poly(siloxane urethane) (S‐PU) copolymers by thermogravimetric analysis (TGA) and thermogravimetric analysis/Fourier transform infrared spectroscopy (TG–FTIR). The stage of initial degradation for E‐PU was demonstrated as a urethane‐B segment consisting of 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butanediol. Moreover, the urethane‐B segment in the copolymers had the lowest temperature of degradation (ca. 200°C). The degradation of E‐PU was determined by TGA and TG–FTIR analyses and had three stages including seven steps. Although the soft segment of S‐PU possessed the thermal stability of polydimethylsiloxane (PDMS), the unstable urethane‐B segment existed in S‐PU. Therefore, the initial degradation of S‐PU appeared around 210°C. The four stages of degradation of S‐PU involved eight steps, as revealed by TG–FTIR, which identified the main decomposition products: CO₂, tetrahydrofuran, and siloxane decomposition products. The imide group with high thermal stability was to replace the urethane‐B segment of S‐PU, which had the lowest thermal stability herein. The poly(siloxane urethane imide) (I‐PU) copolymer around 285°C exhibited a high initial temperature of degradation, and the initial degradation occurred at the urethane‐S segment consisting of MDI and PDMS. The degradation of I‐PU was similar to that of S‐PU and had four stages including six steps. Moreover, the degradation region of the imide group between 468 and 625°C was merged into the degradation stage of the siloxane decomposed products. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Poly(dimethylsiloxane)urethane‐co‐poly(methyl methacrylate) with 2,4‐toluene diisocyanate and m‐xylene diisocyanate. I. Compatibility and impact strength of copolymers

In this study, slightly crosslinked poly(dimethylsiloxane)urethane‐co‐poly(methyl methacrylate) (PDMS urethane‐co‐PMMA) graft copolymers based on two diisocyanates, 2,4‐toluene diisocyanate (2,4‐TDI) and m‐xylene diisocyanate (m‐XDI), were successfully synthesized. Glass‐transition behaviors of the copolymers were investigated. Results confirm that PDMS–urethane and PMMA are miscible in the 2,4‐TDI system, but are only partially miscible in the m‐XDI system. The methylene groups adjoining the isocyanate in the m‐XDI system show increased phase‐separation behavior over the 2,4‐TDI system, in which the benzene ring adjoins the isocyanate. The functional group of PDMS–urethane improves the impact strength of the copolymers. The toughness depends on the compatibility of PDMS–urethane and PMMA segments in the copolymers. In the m‐XDI system, the impact strength of the copolymer containing 3.75 phr macromonomer achieves a maximum value (from 13.02 to 22.21 J/m). The fracture behavior and impact strength of the copolymers in the 2,4‐TDI system are similar to that of PMMA homopolymer, although they are independent of the macromonomer content in the copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1875–1885, 2002     

Synthesis and characterization of copolymers based on poly(butylene terephthalate) and ethylene oxide‐poly(dimethylsiloxane)‐ethylene oxide

A series of thermoplastic elastomers based on ethylene oxide‐poly(dimethylsiloxane)‐ethylene oxide (EO‐PDMS‐EO), as the soft segment, and poly(butylene terephthalate) (PBT), as the hard segment, were synthesized by catalyzed two‐step, melt transesterification reaction of dimethyl terephthalate (DMT) with 1,4‐butanediol (BD) and α,ω‐dihydroxy‐(EO‐PDMS‐EO). Copolymers with a content of hard PBT segments between 40 and 90 mass % and a constant length of the soft EO‐PDMS‐EO segments were prepared. The siloxane prepolymer with hydrophilic terminal EO units was used to improve the miscibility between the polar comonomers, DMT and BD, and the nonpolar PDMS. The molecular structure and composition of the copolymers were determined by ¹H‐NMR spectroscopy, whereas the effectiveness of the incorporation of α,ω‐dihydroxy‐(EO‐PDMS‐EO) into the copolymer chains was verified by chloroform extraction. The effects of the structure and composition of the copolymers on the melting temperatures and the degree of crystallinity, as well as on the thermal degradation stability and some rheological properties, were studied. It was demonstrated that the degree of crystallinity, the melting and crystallization temperatures of the copolymers increased with increasing mass fraction of the PBT segments. The thermal stability of the copolymers was lower than that of PBT homopolymer, because of the presence of thermoliable ether bonds in the soft segments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Crystallization behavior of PEO in blends of poly(ethylene oxide)/poly(2‐vinyl pyridine)‐b‐(ethylene oxide) block copolymer

The crystallization behavior of two molecular weight poly(ethylene oxide)s (PEO) and their blends with the block copolymer poly(2‐vinyl pyridine)‐b‐poly(ethylene oxide) (P2VP‐b‐PEO) was investigated by polarized optical microscopy, thermogravimetric analysis, differential scanning calorimetry, and atomic force microscopy (AFM). A sharp decreasing of the spherulite growth rate was observed with the increasing of the copolymer content in the blend. The addition of P2VP‐b‐PEO to PEO increases the degradation temperature becoming the thermal stability of the blend very similar to that of the block copolymer P2VP‐b‐PEO. Glass transition temperatures, T_g, for PEO/P2VP‐b‐PEO blends were intermediate between those of the pure components and the value increased as the content of PEO homopolymer decreased in the blend. AFM images showed spherulites with lamellar crystal morphology for the homopolymer PEO. Lamellar crystal morphology with sheaf‐like lamellar arrangement was observed for 80 wt% PEO(200M) and a lamellar crystal morphology with grain aggregation was observed for 50 and 20 wt% blends. The isothermal crystallization kinetics of PEO was progressively retarded as the copolymer content in the blend increased, since the copolymer hinders the molecular mobility in the miscible amorphous phase. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Morphology of poly(styrene‐block‐dimethylsiloxane) copolymer films

The morphologies of poly(styrene‐block‐di‐methylsiloxane) (PS‐b‐PDMS) copolymer thin films were analyzed via atomic force microscopy and transition electron microscopy (TEM). The asymmetric copolymer thin films spin‐cast from toluene onto mica presented meshlike structures, which were different from the spherical structures from TEM measurements. The annealing temperature affected the surface morphology of the PS‐b‐PDMS copolymer thin films; the polydimethylsiloxane (PDMS) phases at the surface were increased when the annealing temperature was higher than the PDMS glass‐transition temperature. The morphologies of the PS‐b‐PDMS copolymer thin films were different from solvent to solvent; for thin films spin‐cast from toluene, the polystyrene (PS) phase appeared as pits in the PDMS matrix, whereas the thin films spin‐cast from cyclohexane solutions exhibited an islandlike structure and small, separated PS phases as protrusions over the macroscopically flat surface. The microphase structure of the PS‐b‐PDMS copolymer thin films was also strongly influenced by the different substrates; for an asymmetric block copolymer thin film, the PDMS and PS phases on a silicon substrate presented a lamellar structure parallel to the surface at intervals. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1010–1018, 2007     

Synthesis and surface properties of polydimethylsiloxane‐based block copolymers: poly[dimethylsiloxane‐block‐ (ethyl methacrylate)] and poly[dimethylsiloxane‐block‐(hydroxyethyl methacrylate)]

A polydimethylsiloxane (PDMS) macroazoinitiator was synthesized from bis(hydroxyalkyl)‐terminated PDMS and 4,4′‐azobis‐4‐cyanopentanoic acid by a condensation reaction. The bifunctional macroinitiator was used for the block copolymerization of ethyl methacrylate (EMA) and 2‐(trimethylsilyloxy)ethyl methacrylate (TMSHEMA) monomers. The poly(DMS‐block‐EMA) and poly(DMS‐block‐TMSHEMA) copolymers thus obtained were characterized using Fourier transform infrared and ¹H NMR spectroscopy and differential scanning calorimetry. After the deprotection of trimethylsilyl groups, poly(DMS‐block‐HEMA) and poly(DMS‐block‐EMA) copolymer film surfaces were analysed using scanning electron microscopy and X‐ray photoelectron spectroscopy. The effects of the PDMS concentration in the copolymers on both air and glass sides of films were examined. The PDMS segments oriented and moved to the glass side in poly(DMS‐block‐EMA) copolymer film while orientation to the air side became evident with increasing DMS content in poly(DMS‐block‐HEMA) copolymer film. The block copolymerization technique described here is a versatile and economic method and is also applicable to a wide range of monomers. The copolymers obtained have phase‐separated morphologies and the effects of DMS segments on copolymer film surfaces are different at the glass and air sides. Copyright © 2010 Society of Chemical Industry     

Thermal degradation kinetics of poly(O,O‐diethyl‐O‐allylthiophosphate‐co‐acrylonitrile) in nitrogen

The nonisothermal degradation kinetics of the copolymer poly(O,O‐diethyl‐O‐allylthiophosphate‐co‐acrylonitrile), which was synthesized with O,O‐diethyl‐O‐allylthiophosphate and acrylonitrile, were studied by thermogravimetry/derivative thermogravimetry techniques. The kinetic parameters, including the activation energy and the pre‐exponential factor of the copolymer degradation process, were calculated by the Kissinger and Flynn–Wall–Ozawa methods. The thermal degradation mechanism of the copolymer was also studied with the Satava–Sestak method. The results show that the activation energies were 138.17 kJ/mol with the Kissinger method and 141.63 kJ/mol with the Flynn–Wall–Ozawa method. The degradation of the copolymer followed a kinetic model of a phase boundary reaction and the kinetic equation could be expressed as G(α) = 1 ? (1 ? α)⁴ [where G(α) is the integral function of conversion and α is the extent of conversion of the reactant decomposed at time t]. The reaction order was 4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polymorphism and crystallization in poly(vinylidene fluoride)/ poly(ϵ‐caprolactone)–block–poly(dimethylsiloxane)–block–poly(ϵ‐caprolactone) blends

The miscibility, crystallization kinetics and crystalline morphology of a new system of poly(vinylidene fluoride)/poly(?‐caprolactone)‐block‐poly(dimethylsiloxane)‐block‐poly(?‐caprolactone) (PVDF/PCL‐b‐PDMS‐b‐PCL) triblock copolymer were investigated by a variety of techniques. The miscibility and phase behaviour of PVDF/PCL‐b‐PDMS‐b‐PCL were studied by determination of the melting point temperature, crystallization kinetics and Fourier transform infrared (FTIR) mapping. Chemical imaging was used as a new technique to characterize the interaction of polymer blends in crystalline morphology. The results demonstrate the existence of characteristic peaks of both PVDF and PCL in the chosen crystalline area. The crystalline structures of PVDF were affected by the PCL‐b‐PDMS‐b‐PCL triblock copolymer and facilitate the formation of the β polymorph which was illustrated by FTIR analysis. The β crystal phase fraction increases significantly on increasing the composition of the PCL‐b‐PDMS‐b‐PCL triblock copolymer. In addition, confined crystallization of PCL within PVDF inter‐lamellar and/or inter‐fibrillar regions was confirmed through polarizing optical microscopy, wide‐angle X‐ray diffraction and small‐angle X‐ray scattering analysis. © 2019 Society of Chemical Industry     

ZnO nanoparticles dispersed poly(aniline‐co‐o‐anthranilic acid) composites: Photocatalytic reduction of Cr(VI) and Ni(II)

In this report, poly(aniline‐co‐anthranilic acid)/zinc oxide (poly(ANI‐co‐ANA)/ZnO) nanocomposites were prepared by in‐situ chemical oxidative polymerization. Transmission electron microscopy (TEM), X‐ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy measurements were used to characterize the resulting pure copolymer and nanocomposite. TEM analysis showed that the nanoparticles with a mean diameter of 15–25 nm were dispersed in the copolymer matrix. Thermogravimetric analysis indicated that the nanocomposite had a higher decomposition temperature than the pure copolymer. The conductivity measurements showed the resulting nanocomposite possessed higher conductivity as compared to the pure copolymer. Photocatalytic removal of Cr(VI) and Ni(II) from aqueous solution using as‐synthesized nanocomposite under UV‐light irradiation was studied. The reduction patterns of Cr(VI) and Ni(II) were better fitted to first‐order kinetic model. The nanocomposite was also applied as a photocatalyst for the degradation of methylene blue dye. The result revealed substantial degradation of the dye (∼82%) under UV‐light illumination. POLYM. COMPOS., 35:839–846, 2014. © 2013 Society of Plastics Engineers     

Complexation of poly(dimethylsiloxane)/poly(methyl methacrylate‐co‐butyl acrylate‐co‐methacrylic acid) latex with poly(dimethylsiloxane)/poly(vinyl acetate‐co‐butyl acrylate) latex

Two latices—the poly(dimethylsiloxane) (PDMS)/poly(methyl methacrylate‐co‐butyl acrylate‐co‐methacrylic acid) system (PA latex) and the PDMS/poly(vinyl acetate‐co‐butyl acrylate) system (PB latex)—were prepared by seeded emulsion polymerization, and PA/PB complex latices were obtained through the interparticle complexation of the PA latex with the PB latex. In addition, for the further study of the interparticle complexation of the PA latex with the PB latex, copolymer latices [PDMS/methyl methacrylate‐co‐butyl acrylate‐co‐vinyl acetate‐co‐methacrylic acid) (PC)] were prepared according to the monomer recipe of the complex latices and the polymerization process of the component latices. The properties of the obtained polymer latices and complex latices were investigated with surface‐tension, contact‐angle, and viscosity measurements. The mechanical properties of the coatings obtained from the latices were investigated with tensile‐strength measurements. The results showed that, in comparison with the two component latices (PA latex and PB latex) and the corresponding copolymer latices (PC latices), the PA/PB complex latices had lower surface tension, lower viscosities, and better wettability to different substrates. The tensile strengths of the coatings obtained from the complex latices were higher than the tensile strengths of the coatings from the two component latices and copolymer latices. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2522–2527, 2004     

Thermal decomposition kinetics of poly(nButMA‐b‐St) diblock copolymer synthesized by ATRP

The reaction mechanism of decomposition process and the kinetic parameters of the poly(n‐butyl methacrylate‐b‐styrene), poly(nButMA‐b‐St), diblock copolymer synthesized by atom transfer radical polymerization (ATRP) were investigated by thermogravimetric analysis (TGA) at different heating rates. TGA curves showed that the thermal decomposition occurred in one stage. The apparent activation energies of thermal decomposition for copolymer, as determined by the Kissinger's, Flynn–Wall–Ozawa and Tang methods, which does not require knowledge of the reaction mechanism (RM), were 112.52, 116.54, and 113.41 kJ/mol, respectively. The experimental results were compared with master plots, in the range of the Doyle approximation. Analysis of experimental results suggests that in the conversion range studied, 3–18%, the actual RM is an A₂ sigmoidal type. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Kinetics of thermal degradation of thermotropic poly(p‐oxybenzoate‐co‐ethylene‐2,6‐naphthalate) by single heating rate methods

The kinetics of thermal degradation of thermotropic liquid crystalline poly(p‐oxybenzoate‐co‐ethylene‐2,6‐naphthalate) (PHB/PEN) with the monomer ratio of 60 : 40 and PEN in nitrogen was studied by dynamic thermogravimetry (TG). The kinetic parameters, including the activation energy E_a, the reaction order n, and the frequency factor ln(Z) of the degradation reaction for PHB/PEN (60 : 40) and PEN were analyzed by the single heating rate methods of Friedman and Chang. The effects of the heating rate and the calculating method on the thermostable and degradation kinetic parameters are systematically discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3915–3920, 2004     

Microphase separation behavior on the surfaces of poly(dimethylsiloxane)‐block‐poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) diblock copolymer coatings

Microphase separation behavior on the surfaces of poly(dimethylsiloxane)‐block‐poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) (PDMS‐b‐PHFBMA) diblock copolymer coatings was investigated. The PDMS‐b‐PHFBMA diblock copolymers were successfully synthesized via atom transfer radical polymerization (ATRP). The chemical structure of the copolymers was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Surface composition was studied by X‐ray photoelectron spectroscopy. Copolymer microstructure was investigated by atomic force microscopy. The microstructure observations show that well‐organized phase‐separated surfaces consist of hydrophobic domain from PDMS segments and more hydrophobic domain from PHFBMA segments in the copolymers. The increase in the PHFBMA content can strengthen the microphase separation behavior in the PDMS‐b‐PHFBMA diblock copolymers. And the increase in the annealing temperature can also strengthen the microphase separation behavior in the PDMS‐b‐PHFBMA diblock copolymers. Moreover, Flory‐Huggins thermodynamic theory was preliminarily used to explain the microphase separation behavior in the PDMS‐b‐PHFBMA diblock copolymers.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal decomposition kinetics of thermotropic poly(oxybenzoate‐co‐trimethylene terephthalate)

A new kind of thermotropic liquid crystalline, poly(oxybenzoate‐co‐trimethylene terephthalate), was prepared from p‐hydroxybenzoic acid (B) and poly(trimethylene terephthalate) (PTT or T) by melting polycondensation. The monomer ratio of B to T is 60:40. The dynamic thermogravimetric kinetics of the copolymer B/T (60:40) and PTT in nitrogen were analyzed by four single heating rate techniques and two multiple heating rate techniques. The effects of the heating rate and the calculating technique on the thermostable and degradation kinetic parameters of the B/T copolymer and PTT are systematically discussed. The four single heating rate techniques used in this work include Friedman, Freeman‐Carroll, Chang, and the second Kissinger techniques, whereas the two multiple heating rate techniques are the first Kissinger and Flynn‐Wall techniques. Additionally, the isothermal thermogravimetric kinetics of B/T (60:40) in nitrogen were investigated by the Flynn technique. The activation energy, the order, and the frequency factor of the degradation reaction for B/T (60:40) copolymer are determined to be 185 kJ/mol, 1.8, and 7.14 × 10¹³ min⁻¹, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2025–2036, 2000     

Compatibilizing effect of poly(styrene)‐block‐poly(isoprene) copolymers in heterogeneous poly(styrene)/natural rubber blends

Compatibility of poly(styrene) (PS)/natural rubber (NR) blend is improved by the addition of diblock copolymer of poly(styrene) and cis‐poly(isoprene) (PS‐b‐PI). The compatibilizing effect has been investigated as a function of block copolymer molecular weight, composition and concentration. The effect of homopolymer molecular weight, processing conditions and mode of addition on the morphology of the dispersed phase have also been investigated by means of optical microscopy and scanning electron microscopy. A sharp decrease in phase dimensions is observed with the addition of a few percent of block copolymers. The effect levels off at higher concentrations. The leveling off could be an indication of interfacial saturation. For concentrations below the critical value, the particle size reduction is linear with copolymer volume fraction and agrees well with the prediction of Noolandi and Hong. The addition of the block copolymer improves the mechanical properties of the blend. An attempt is made to correlate the mechanical properties with the morphology of the blends. © 2001 Society of Chemical Industry     

Effect of thermomechanical history on the crystallization of poly(ether‐block‐amide)

The quiescent and flow‐induced crystallization of a poly(ether‐block‐amide) is studied by means of rheo‐optical methods. Both optical microscopy and small angle light scattering have been used. The multiblock copolymer has a microphase‐separated structure with an order–disorder transition at 180–185°C, as measured with rheometry and SAXS. The number of nuclei, spherulitic growth rates, and the characteristic time scale for crystallization are compared with that of a polyamide of similar molar mass. For the poly(ether‐block‐amide)—containing a majority of amide segments—the growth rates of the spherulites during quiescent crystallization are similar for the block copolymer and the homopolymer, even if the spherulitic structures are not the same. When flow is applied, the two materials behave differently. The flow increased the nucleation density in the homopolymer but not in the block copolymer. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

A study on thermal behavior of a poly(VDF‐CTFE) copolymers binder for high energy materials

This article describes a study on thermal behavior of poly(vinylidene fluoride‐chlorotrifluoroetheylene) [poly(VDF‐CTFE)] copolymers as polymeric binders of specific interest for high energy materials (HEMs) composites by thermal analytical techniques. The non‐isothermal thermogravimetry (TG) for poly (VDF‐CTFE) copolymers was recorded in air and N₂ atmospheres. The results of TG thermograms show that poly(VDF‐CTFE) copolymers get degrade at lower temperature when in air than in N₂ atmosphere. In the derivative curve, there was single maximum degradation peak (T_max) indicating one‐stage degradation of poly(VDF‐CTFE) copolymers for all the samples. The other thermal properties such as glass transition temperature (T_g) and degradation temperature (T_d) for poly(VDF‐CTFE) copolymers were measured by employing differential scanning calorimeter (DSC) technique. The kinetic parameters related to thermal degradation of poly(VDF‐CTFE) copolymers were investigated through non‐isothermal Kissinger kinetic method using DSC method. The activation energies for thermal degradation of poly(VDF‐CTFE) copolymers were found in a range of 218–278 kJ/mol. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Silicone hydrogels based on a novel amphiphilic poly(2‐methyl‐2‐oxazoline)‐b‐poly(dimethyl siloxane) copolymer

A novel amphiphilic hydrogel based on poly(2‐methyl‐2‐oxazoline)‐b‐poly(dimethyl siloxane) (PMeOx–PDMS) block copolymer was developed. First of all, PMeOx–PDMS macromonomer was synthesized by coupling mono‐hydroxylated PMeOx with PDMS followed by end‐capping with methacrylate group. The structures of each step were characterized by NMR and titration. After that, silicone hydrogels were prepared by UV‐initiated copolymerization of PMeOx–PDMS macromonomer with monomers such as 2‐hydroxyethyl methacrylate in the presence of a crosslinker. Measurements of the hydrogels' water contact angle, equilibrium water content, and tensile properties showed that the hydrogels possessed better hydrophilic surface, higher water content, and better ion permeability with the increase of the content of the macromonomer PMeOx–PDMS. Meanwhile, the tensile strength and Young's modulus of the hydrogels decreased slightly. Protein adsorption tests showed that the hydrogels had strong antifouling ability after the incorporation of PMeOx. This newly described hydrogel demonstrated attractive properties to serve as ophthalmic biomaterial. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39867.