Synthesis and characterization of polyimide/hexagonal boron nitride composite

Polyimide (PI)/hexagonal boron nitride (h‐BN) composites were produced via the thermal imidization procedure from solution mixtures of a polyamicacid, which is prepared from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 3,3′‐diaminodiphenyl sulfone (DADPS) in N‐methyl‐2‐pyrrolidone (NMP), and alkoxysilane functionalized h‐BN. The structure, thermostability, thermal behavior, and surface properties of the resulting materials were characterized by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). The thermal characteristics of PI/h‐BN films were better than the pure PIs. The physical and mechanical properties of the films were evaluated by various techniques such as contact angle, chemical resistance, and tensile tests. The flame retardancy of the composite materials was also examined by the limiting oxygen index (LOI). The experiments showed that the LOI values of PIs increased from 32 to 43 for the materials containing hexagonal boron nitride. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and properties of organosoluble,colorless, and high‐pretilt‐angle polyimides based on an alicyclic dianhydride and long‐main‐chain alkyl‐group‐containing diamines

Alicyclic polyimides (PIs) were prepared from 3‐carboxylmethyl‐cyclopentane‐1,2,4‐tricarboxylic acid dianhydride and α,ω‐di(4‐aminophenoxyl)alkanes. These PIs possessed good solubility in aprotic, strongly polar solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethyl formamide, and m‐cresol. They possessed high transparency in visible wavelengths and were almost colorless. The pretilt angle of a liquid‐crystal display with these PIs as the alignment layer increased linearly as the length of the alkyloxy groups increased; it was close to 5° for the PI samples PI‐10 and PI‐12. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2814–2820, 2001     

Sol‐Gel Materials, 1. Synthesis and Hydrolytic Condensation of New Cross‐Linking Alkoxysilane Methacrylates and Light‐Curing Composites Based upon the Condensates

New methacryloyloxyalkylaminoalkylalkoxysilanes have been synthesised by Michael addition of the corresponding acryloyloxyalkyl methacrylates with (3‐aminopropyl)triethoxysilane (APTES). Low‐viscosity polycondensates have been formed by hydrolysis and condensation of these silanes in the presence of ammonium fluoride (NH₄F). The reaction of APTES with the addition product of succinic or glutaric anhydride with glycerol dimethacrylate results in the formation of new dimethacrylate‐functionalised 3‐amidopropyltriethoxysilanes. The hydrolytic condensation of these silanes was carried out in the presence of 0.5 M HCl. The hydrolysis and condensation of the silanes have been studied by ²⁹Si NMR spectroscopy. Cross‐linked inorganic‐organic materials have been obtained by free‐radical photopolymerisation of the polycondensates and their mixtures in the presence of camphorquinone and ethyl 4‐(dimethylamino)benzoate with visible light (VL). The synthesised polycondensates enable the preparation of diluent‐free composites. The mechanical properties of VL‐cured polycondensates and composites have been investigated.     

A comparative study on effect of aromatic polyimide chain conformation on reinforcement of carbon nanotube/polyimide nanocomposites

Two kinds of polyimides (PIs) were selected as matrices for multiwalled carbon nanotubes (CNTs)‐based nanocomposites. The two PIs were initially synthesized through reactions of a same benzoxazole‐containing diamine with two different dianhydrids. A linear PI was formed from the ether bond‐containing dianhydride, while a nonlinear PI was formed from the ? C(CF3)_2? groups containing dianhydride. Optimized dispersion of nanotubes in both kinds of PIs was found to be at a concentration with 0.5 wt % COOH‐CNT, where great enhancement was achieved for both PIs. It was also found that introducing nanotubes into PI matrices aroused more significant increase of Young's modulus and break stress in linear PI than that in nonlinear PI. To determine the key parameters involved in design of PIs for maximum reinforcement efficiency using CNT as the nanofiller, the nanoscopic dispersion state of the nanotubes in diamine solution and their reaction were investigated via morphological and spectroscopic studies. The interfacial interactions between nanotubes and two PI chains were characterized by FT‐IR and Raman spectroscopy. The fracture surface characteristics of two series of CNT/PI nanocomposites were further investigated using SEM. Our findings show that the diamine plays a double role for the in‐situ polymerization, a dispersant to disentangle the CNT agglomerates and a monomer for PI synthesis with dianhydrides. It was also found that geometry and flexibility of PI chains are crucial to determine the interfacial interactions between nanotubes and PI chains. For elucidating the different interfacial characteristics of the two PIs on the surface of CNT, we proposed a model for preferred conformation adopted by a single PI chain on a single CNT. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40479.     

Evaluation of Difunctional Vinylcyclopropanes as Reactive Diluents for the Development of Low‐Shrinkage Composites

Polymerization shrinkage of dental composites remains a major concern. Free‐radically polymerizable cyclic monomers can be a conceivable alternative to methacrylates for the development of low‐shrinkage composites. In this study, the one‐step synthesis of the novel low viscosity difunctional vinylcyclopropanes 1 – 4 is described. Photopolymerization kinetics of these monomers are investigated by photo‐differential scanning calorimeter, using bis(4‐methoxybenzoyl)diethylgermane as photoinitiator. Real‐time near‐infrared photorheology measurements are performed to evaluate rheological behavior (i.e., time of gelation, polymerization‐induced shrinkage force) and chemical conversion (i.e., double bond conversion at the gel point, final double bond conversion) of the vinylcyclopropanes in situ. The potential of these monomers as reactive diluents in dental restorative materials is evaluated. Composites based on vinycyclopropanes 1 – 4 show good mechanical properties and exhibit significantly lower volumetric shrinkage and shrinkage stress than corresponding dimethacrylate‐based materials. The results indicate that such monomers are promising candidates for the replacement of commonly used low viscosity dimethacrylates such as triethylene glycol dimethacrylate in dental composites.

     

Synthesis and Light‐Emitting Properties of New Polyimides Containing Ethynylene Units in the Main Chain

Two new polyimides (ODA‐PI and HDA‐PI) having 1,4‐phenylenediethynylene unit and octyloxy groups were synthesized. Judging from inherent viscosities of their precursor PAAs (1.42 and 1.62 dL · g^?1), the two PIs were very high in molecular weight. Casting and thermal imidization of PAAs results polyimides with good‐quality films. They were stable up to 364 °C and showed no crystallites. UV‐vis and PL spectra in NMP solutions of both PIs showed maxima at 442 and 501 nm, respectively, while PL spectra in ≈10 µm thick films exhibited a maximum at 540 nm. CV indicates that two PIs were electrochemically active in redox region. The devices with construction of ITO/PEDOT/PIs/BAlq₃/LiF/Al exhibited turn‐on voltages of 6.5 V in ODA‐PI and 7.5 V in HDA‐PI and emitted a bright bluish‐green light. ODA‐PI and HDA‐PI showed maximum luminescence of 256 and 316 cd · cm^?2, respectively, at the same voltage of 12 V.

     

Electrically bistable digital memory behaviors of thin films of polyimides based on conjugated bis(triphenylamine) derivatives

Three functional polyimides (PIs) bearing conjugated bis(triphenylamine) (2TPA) derivatives with electron-donating and accepting groups were synthesized with reasonably high molecular weights. The PIs exhibited high thermal and dimensional stabilities and furthermore produced high-quality nanoscale thin films via conventional solution coating process. All of the PIs in the films were found to be amorphous, but they were oriented somewhat preferentially in the film plane, rather than randomly. Their film densities and interchain distances were measured, and the optical and electrochemical properties were determined. All of the PIs in the devices with aluminum top and bottom electrodes initially revealed a high resistance (OFF-state). However, under positive and negative voltage sweeps, the PIs demonstrated volatile or nonvolatile digital memory behavior, depending on the substituents of the 2TPA unit. The 2TPA-based PI, as well as the PI bearing 2TPA with electron-donating methoxy substituents showed unipolar write-once-read-many-times (WORM) memory behavior, whereas the 2TPA-based PI containing electron-accepting cyano groups exhibited unipolar dynamic random access memory (DRAM) behavior. All of the PI films revealed excellent retention abilities in both the OFF- and ON-state, even under ambient air conditions. Moreover, they all revealed high ON/OFF current ratios (10⁶–10¹⁰). All of the memory behaviors were found to be governed by a mechanism involving trap-limited space-charge limited conduction and local filament formation. Such memory behaviors were further investigated in detail with taking into consideration the PI components' chemical nature and molecular orbital levels, possible trapping sites, substituents' effect, and the metal electrodes' work function. Overall, this study demonstrated that the thermally, dimensionally stable PIs are highly suitable for the low-cost mass production of high performance, polarity-free digital memory devices that can be operated with very low power consumption. Moreover, the memory mode can be tuned by changing the substituent in the 2TPA unit.     

Synthesis of highly transparent and heat‐resistant polyimides containing bulky pendant moieties

A new diamine with bulky pendant biphenyl and ortho‐position dimethyl structures, 4,4′‐((1,1′‐biphenyl)‐4‐ylmethylene)bis(2,6‐dimethylaniline), was synthesized via a one‐pot reaction of 4‐biphenyl carboxaldehyde and 2,6‐dimethylaniline. The diamine was employed to polymerize with several dianhydrides via one‐step condensation under high‐temperature conditions. The light yellow or colorless polyimide (PI) films obtained were found to have cut‐off wavelengths in the range 286–358 nm and transmittance over 80% in the visible region (400–780 nm). Meanwhile, these PIs possessed excellent solubility in common organic solvents, even in low‐boiling‐point solvents such as chloroform (CHCl₃), dichloromethane (CH₂Cl₂) and tetrahydrofuran. The glass transition temperatures (T_g) of the PIs were determined to exceed 343 °C, even to 456 °C. All PI films were flexible with a tensile strength of 78–119 MPa, a Young's modulus of 2.0–2.5 GPa and elongation at break of 4.0%–8.2%. Therefore, these colorless PIs can be used as candidate materials for flexible display substrates. © 2019 Society of Chemical Industry     

Synthesis and properties of novel polyimide optical materials with different haloid pendant

To investigate the difference of trifluoromethyl group and chlorine group affecting the optical properties of polyimides (PIs), two diamine monomers with different haloid pendants were designed and synthesized including (1,4‐(4‐amino‐2‐trifluoromethylphenoxy)‐2‐(3′5′‐ditrifluoromethylphenyl)benzene and (1,4‐(4‐amino‐2‐trifluoromethylphenoxy)‐2‐(3′‐trifluoromethyl‐4′‐chlorophenyl) benzene). From both diamines, two series of PIs with different haloid pendants were prepared via two‐step chemical imidization methods with various dianhydride compounds. All the PIs have the high T_g, excellent thermal stability and good solubility, and can be formed the transparent, strong, and flexible films. All the PIs also are good transparent in UV‐evisible absorption spectra, and have the low birefringences (0.0128–0.0157 at 650 nm) and low optical loss at communication windows. Two series of PIs exhibit the similar optical properties, except for refractive index. Based on the fantastic characterization, a series of optical materials with the tunable refractive indices were obtained by copolymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Colorless polyimides with low coefficient of thermal expansion derived from alkyl‐substituted cyclobutanetetracarboxylic dianhydrides

Alkyl‐substituted cyclobutanetetracarboxylic dianhydrides (CBDAs) were synthesized by photo‐dimerization of alkyl‐substituted maleic anhydrides to obtain novel colorless polyimides (PIs). Dimethyl‐substituted CBDA (DM‐CBDA) showed much higher polymerizability with various diamines than conventional cycloaliphatic tetracarboxylic dianhydrides and led to high molecular weights of PI precursors. Polyaddition of non‐substituted CBDA and trans‐1,4‐cyclohexanediamine (t‐CHDA) was completely inhibited by salt formation in the initial reaction stage. The use of DM‐CBDA allowed the formation of a homogeneous/viscous PI precursor solution by overcoming the salt formation problem. The prominent substituent effect probably reflects how the methyl substituents of DM‐CBDA contributed to increasing the salt solubility. Some of the thermally imidized DM‐CBDA‐based systems simultaneously possessed non‐coloration, low coefficient of thermal expansion (CTE), very high T_g exceeding 300 °C and very low dielectric constant. Copolymerization was very effective for improving the solubility of DM‐CBDA‐based PIs. The copolyimide cast films prepared via chemical imidization displayed a further decreased CTE without sacrificing other target properties, suggesting that the present materials can be useful as plastic substrates in display devices. The mechanism of self‐chain orientation behavior during solution casting is also discussed. A potential application of the copolyimide systems as optical compensation film materials in liquid crystal displays is proposed. © 2013 Society of Chemical Industry .     

Polymerization shrinkage,stress, and degree of conversion in silorane‐ and dimethacrylate‐based dental composites

To compare two kind of resin‐based dental composites, the polymerization shrinkage, contraction stress (CS), and degree of conversion (DC) of four dimethacrylate‐based and one silorane‐based composite were investigated. To determine shrinkage, the composites were packed, respectively, into a cylindrical cavity in human teeth and imaged using X‐ray microcomputed tomography to determine the precise volume before and 30 min after photopolymerization. To determine CS, the sample was applied in a similarly sized cylinder in a universal testing machine and monitored for 30 min. FTIR spectroscopy was used to determine DC. The volumetric shrinkage (range: 1.1–3.1%) and maximum CS (range: 1.2–3.5 MPa) differed significantly among the tested composites but not the final DC (range: 62.3–69.1%). The silorane‐based composite displayed the lowest volumetric shrinkage and CS of all composites. No correlation was observed between the stress and volumetric shrinkage values of the dimethacrylate‐based composites. A moderate correlation was found between stress and DC (r = 0.836), which was significant at 20 and 40 s. The silorane‐based composite exhibited superior shrinkage behavior compared with conventional dimethacrylate composites with comparable polymerization kinetics. The CS was dependent on multiple variables, including the volumetric shrinkage, DC, and curing rate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Efficiency of 4,4′‐bis(N,N‐diethylamino) benzophenone for the polymerization of dimethacrylate resins in thick sections

The efficiency of 4,4′‐bis(N,N‐diethylamino)benzophenone (DEABP) for the polymerization of dimethacrylate monomers in thick sections ( 1 – 2 mm) was studied. DEABP (λ_max = 365 nm) represents a complete initiating system as it contains both ketone and amine functional groups. During irradiation, DEABP photobleaches at a fast rate causing deeper penetration of light through the underlying layers, but the photoinitiation efficiency (rate of polymerization per photon absorption rate) is relatively poor. As a result, irradiation of methacrylate monomers at 365 nm results in a slow average polymerization rate and a reduced monomer conversion for thick sections due to the light attenuation caused by the high absorptivity of DEABP and photolysis products. These results highlight the inherent interlinking of light attenuation and photobleaching rate in polymerization of thick sections. Copyright © 2011 Society of Chemical Industry     

Polymerization of Cyclic Monomers, 12

Summary: The radical polymerization of different substituted methyl 2‐(bicyclo[3.1.0]hex‐1‐yl) acrylates, 1a – f , was initiated by 2,2′‐azoisobutyronitrile (AIBN) at 65 °C in chlorobenzene. The radical homopolymerization of 1a – f occurred through the opening of the cyclopropane ring, and lead to polymers with number‐average molecular weights of 13 000 to 434 400 g · mol^?1 and glass transition temperatures between 77 and 121 °C. The monomers 1a – f showed a similar reactivity to MMA (in the copolymerization with MMA). Selected monomers were determined to be diluent monomers for dental filling composites and enable the preparation of composites that show a significantly reduced polymerization shrinkage, compared to composites based on dimethacrylate diluents.

     

Effect of maleic anhydride/vinyltrimethoxysilane‐co‐grafting polypropylene on the properties of wood‐flour/polypropylene composites by electron‐beam preirradiation

The electron‐beam preirradiation and reactive extrusion technologies were used to prepare maleic anhydride (MAH)/vinyltrimethoxysilane (VTMS)‐co‐grafting polypropylene (PP) as a high‐performance compatibilizer for wood‐flour/PP composites. The grafting content, chemical structure, and crystallization behavior of the compatibilizers were characterized through Fourier transform infrared spectroscopy, differential scanning calorimetry, and an extraction method. The effects of the compatibilizers on the mechanical properties, water absorption, morphological structure, and torque rheological behavior of the composites were investigated comparatively. The experimental results demonstrate that MAH/VTMS‐g‐PP markedly enhanced the mechanical properties of the composites. Compared with MAH‐g‐PP and VTMS‐g‐PP, MAH/VTMS‐g‐PP clearly showed synergistic effects on the increasing mechanical properties, water absorption, and compatibility of the composites. Scanning electron microscopy further confirmed that the adhesion and dispersion of wood flours in the composites were effectively improved by MAH/VTMS‐g‐PP. These results were also proven by the best water resistance of the wood‐flour/PP composites with MAH/VTMS‐g‐PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Modification of cyanate ester resin by soluble polyimides

Soluble polyimides (PIs) were prepared as random or multiblock types with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA) as acid dianhydride components and 4,4′‐bis(m‐aminophenoxy) diphenyl sulfone (m‐BAPS) as a diamine component by a one‐pot process and used to improve the brittleness of the cyanate ester resin. Random‐type PIs were more effective as modifiers than multiblock‐type PIs. The morphologies of the modified resins depended on PI structure, molecular weight, and concentration. The most effective modification of the cyanate ester resin was attained because of a heterogeneous phase structure composed of a flat matrix phase and phase‐inverted structures of the modified resin; a 15 wt % inclusion of a random PI (weight‐average molecular weight = 63,400) composed of 6FDA, s‐BPDA, and m‐BAPS (0.5/0.5/1.0 molar ratio) led to a 65% increase in the fracture toughness for the modified resin with a slight loss of flexural strength and a retention of flexural modulus and glass‐transition temperature, compared with the values for the unmodified resin. Water absorptivity of the modified resin was comparable to that of the unmodified resin up to 400 h, and then, water absorption of the modified resins increased considerably. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1–11, 2003     

Effect of the structure of silane‐coupling agent on dynamic mechanical properties of dental resin‐nanocomposites

This work was aimed at the study by dynamic mechanical analysis (DMA) of dental composites consisted of a Bis‐GMA/TEGDMA (50/50 wt/wt) matrix and silica nanoparticles (Aerosil OX50) as filler, silanized with various silanes. The silanes used were 3‐[(1,3(2)‐dimethacryloyloxypropyl)‐2 (3)‐oxycarbonylamido] propyltriethoxy‐silane (UDMS), 3‐methacryloxypropyl‐trimethoxysilane (MPS), octyltrimethoxysilane (OTMS), blends of UDMS/OTMS (50/50 wt/wt), or MPS/OTMS (50/50 wt/wt). The total amount of silane was kept constant at 10% by weight fraction relative to the filler weight. The silanized nanoparticles were mixed with the dimethacrylate matrix (60% filler by weight fraction). The composites were light cured and tested by DMA for the determination of storage modulus (E′), loss modulus (E″), tangent delta (tan δ), and glass transition temperature (T_g). Measurements were performed in samples immediately after curing and samples stored in water at 37°C for 1, 7, 30, or 120 days. OTMS‐composite in which OTMS does not form covalent bond with the dimethacrylate matrix showed lower elastic modulus both in dry and wet conditions. The ability of bifunctional UDMS for crosslinking was found not to increase the elastic behavior of the composite, as it was expected, compared with that of MPS‐composite, because of the high amount of the silane used. After immersion in water the elastic modulus of OTMS‐composite remained constant, while that of the other composites increased after 1 day and then remained constant up to 120 days. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Siloxane Core-Modified Organo Soluble Novel Polyimide/Multi-walled Carbon Nanotube Nanocomposites

Siloxane core-modified polyimides (PI)/multi-walled carbon nanotubes (MWCNTs) nanocomposites were designed and developed. The confinement of segmental motion of the PI chain due to high dispersion uniformity of the MWCNTs caused the increment in the glass transition temperature (T _g ) and remarkable elevated thermal stability. All the PIs could afford better solubility with high dielectric constants of 3.5–5.9 and low water absorptions of 0.42–0.68%. These PIs emitted a strong blue fluorescent at 380 nm, assigning the structural confirmation of PI matrix. Heterogeneous morphology of MWCNT/PI nanocomposites was evidenced by SEM and TEM images, resulted from the incorporation of MWCNT.     

Syntheses,characterization, and hydrolytic degradation of P(ε‐caprolactone‐co‐δ‐valerolactone) copolymers: Influence of molecular weight

Biodegradable poly(ε‐caprolactone‐co‐δ‐valerolactone) copolymers were synthesized and investigated to study their behavior in aqueous medium. The copolyesters were produced by ring opening polymerization between ε‐caprolactone (CL) and δ‐valerolactone (VL) in bulk at 140°C using tin(II) octoate as catalyst. They were characterized by using ¹H NMR, size exclusion chromatography, differential scanning calorimetry, and MALDI TOF mass spectrometry. Reactivity ratio determination gave an insight on their microstructure. Hydration, hydrolytic degradation, and biocide release of P(CL‐VL) films with different molecular weights values were studied. A one‐order kinetic whose rate constant decreases with copolymer macromolecular weight was observed. Although the molecular weight decrease remained relatively weak after 8 months of immersion, a correlation between molecular weight and hydrolysis rate was shown by high performance liquid chromatography‐mass spectrometry. The ability of the P(CL‐VL) films to release active compounds dispersed in the films was studied by atomic absorption spectroscopy. The release behavior of all copolymers was identical with a zero‐order kinetic. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43007.     

Synthesis and asymmetric nanofiltration membrane performance of heterogeneously sulfonated aromatic polyimides

Soluble sulfonated polyimides (PI) were heterogeneously synthesized by reacting soluble PIs with sulfur trioxide and dichloromethane solvent. The sulfonated PIs were soluble in polar solvents like N‐methyl‐2‐pyrrolidone (NMP) and N,N'‐dimethylformamide. The sulfonated PIs were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, triangular phase diagram, and back titration. Asymmetric nanofiltration membranes were prepared by the phase inversion method from the casting solution containing NMP and diethyleneglycol dimethylether (DGDE). Introducing DGDE as an additive in the casting solution decreased pore size. The rejection rates of organic molecules and salts were investigated. The observed salt rejection of the membrane was of the order R(Na₂SO₄) > R(NaCl) > R(CaCl₂). The membrane morphology was investigated by scanning electron microscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2483–2489, 2003     

Fluorescent,electroactive, thermally stable triphenylamine‐ and naphthalene‐based polyimides for optoelectronic applications

To tune the photophysical properties of polyimides (PIs), a diamine containing naphthalene and triphenylamine units, N¹‐(4‐aminophenyl)‐N¹‐[(4‐naphthalene‐2‐yloxy)phenyl]benzene‐1,4‐diamine (DA), was synthesized. A series of fluorescent electroactive new PIs from synthesized DA were prepared with conventional thermal imidization with dianhydride. The selected dianhydride were used to study and compare the effects of rigid planar phenyl, flexible phenoxy, and nonplanar flexible hexafluoroisopropyidene and carbonyl groups in the main polymer backbone on the optoelectronic properties and processability of materials. The structures of the synthesized diamine and its PIs were evaluated by spectral and CHNS elemental analysis. The optoelectronic and thermal properties of PIs revealed intense blue‐light emission (428–477 nm), a low oxidation potential (0.3–1.3 V), and a lower highest occupied molecular orbital–lowest unoccupied molecular orbital gap (2.92–3.21 eV). The observed behavior and properties of our synthesized PIs suggest their potential as future hole‐transport materials in optoelectronic applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44526.