Synthesis of soluble and thermally stable polyimides from 3,5‐diamino‐N‐(4‐(8‐quinolinoxy) phenyl) aniline and various dianhydrides

Three novel polyimides (PIs) having pendent 4‐(quinolin‐8‐yloxy) aniline group were prepared by polycondensation of a new diamine with commercially available tetracarboxylic dianhydrides, such as pyromellitic dianhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bicyclo[2.2.2]‐oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride. These PIs were characterized by FTIR, ¹H NMR, and elemental analysis; they had high yields with inherent viscosities in the range of 0.4–0.5 dl g⁻¹, and exhibited excellent solubility in many organic solvents such as N,N‐dimethyl acetamide, N,N′‐dimethyl formamide, N‐methyl pyrrolidone (NMP), dimethyl sulfoxide, and pyridine. These PIs exhibited glass transition temperatures (T_g) between 250 and 325° C. Their initial decomposition temperatures (T_i) ranged between 270 and 450°C, and 10% weight loss temperature (T₁₀) up to 500°C with 68% char yield at 600°C under nitrogen atmosphere. Transparent and hard polymer films were obtained via casting from their NMP solutions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of organosoluble polyfluorinated polyimides derived from 3,3′,5,5′‐tetrafluoro‐4,4′‐diaminodiphenylmethane and various aromatic dianhydrides

A polyfluorinated aromatic diamine, 3,3′, 5,5′‐tetrafluoro‐4,4′‐diaminodiphenylmethane (TFDAM), was synthesized and characterized. A series of polyimides, PI‐1–PI‐4, were prepared by reacting the diamine with four aromatic dianhydrides via a one‐step high‐temperature polycondensation procedure. The obtained polyimide resin had moderate inherent viscosity (0.56–0.68 dL/g) and excellent solubility in common organic solvents. The polyimide films exhibited good thermal stability, with an initial thermal decomposition temperature of 555°C–621°C, a 10% weight loss temperature of 560°C–636°C, and a glass‐transition temperature of 280°C–326°C. Flexible and tough polyimide films showed good tensile properties, with tensile strength of 121–138 MPa, elongation at break of 9%–12%, and tensile modulus of 2.2–2.9 GPa. The polyimide films were good dielectric materials, and surface and volume resistance were on the order of a magnitude of 10¹⁴ and 10¹⁵ Ω cm, respectively. The dielectric constant of the films was below 3.0 at 1 MHz. The polyfluorinated films showed good transparency in the visible‐light region, with a cutoff wavelength as low as 302 nm and transmittance higher than 70% at 450 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1442–1449, 2007     

Low dielectric thermoset. I. Synthesis and properties of novel 2,6‐dimethyl phenol‐dicyclopentadiene epoxy

A 2,6‐dimethyl phenol‐dicyclopentadiene novolac was synthesized from dicyclopentadiene and 2,6‐dimethyl phenol, and the resultant 2,6‐dimethyl phenol‐dicyclopentadiene novolac was epoxidized to 2,6‐dimethyl phenol‐dicyclopentadiene epoxy. The structures of novolac and epoxy were confirmed by Fourier transform infrared spectroscopy (FTIR), elemental analysis, mass spectroscopy (MS), nuclear magnetic resonance spectroscopy (NMR), and epoxy equivalent weight titration. The synthesized 2,6‐dimethyl phenol‐dicyclopentadiene epoxy was then cured with 4,4‐diaminodiphenyl methane (DDM), phenol novolac (PN), 4,4‐diaminodiphenyl sulfone (DDS), and 4,4‐diaminodiphenyl ether (DDE). Thermal properties of cured epoxy resins were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), dielectric analysis (DEA), and thermal gravimetric analysis (TGA). These data were compared with those of the commercial bisphenol A epoxy system. Compared with the bisphenol A epoxy system, the cured 2,6‐dimethyl phenol‐ dicyclopentadiene epoxy resins exhibited lower dielectric constants (～3.0 at 1 MHz and 2.8 at 1 GHz), dissipation factors (～0.007 at 1 MHz and 0.004 at 1 GHz), glass transition temperatures (140–188°C), thermal stability (5% degradation temperature at 382–404°C), thermal expansion coefficients [50–60 ppm/°C before glass‐transition temperature (T_g)], and moisture absorption (0.9–1.1%), but higher modulus (～2 Gpa at 60°C). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2607–2613, 2003     

Synthesis and characterization of a novel acetylene‐ and maleimide‐terminated benzoxazine and its high‐performance thermosets

A novel acetylene‐ and maleimide‐terminated benzoxazine, 3‐(3‐ethynylphenyl)‐3,4‐dihydro‐2H‐6‐(N‐maleimido)‐1,3‐benzoxazine (MBZ‐apa), was successfully synthesized with N‐(4‐hydroxyphenyl)maleimide, paraformaldehyde, and 3‐aminophenylacetylene. The structure of the benzoxazine is confirmed by FTIR and ¹H‐NMR spectroscopies. MBZ‐apa is easily dissolved in common organic solvents. Differential scanning calorimetry (DSC) was used to study thermal cross‐linking behavior of MBZ‐apa. The DSC curve shows only a single exothermic peak due to the oxazine ring‐opening polymerization and the polymerization of the acetylene and maleimide groups occurring simultaneously in the same temperature range. Dynamic mechanical analyses (DMA) reveals that the novel polybenzoxazine exhibits high glass‐transition temperature (T_g) (ca. 348°C). The storage modulus arrives at 4.5 GPa in the range of room temperature to 330°C. The polybenzoxazine exhibits good thermal stability as evidenced by thermogravimetric analysis (TGA). Pyrolysis‐gas chromatography/mass spectrometry (Pyrolysis‐GC/MS) was employed to characterize the polybenzoxazine. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of epoxy film cured with phosphorous‐containing phenolic resin

Through the electrophilic addition reaction of ? P(O)? H and C?C, a series of novel phosphorus‐containing phenolic resins bearing maleimide (P‐PMFs) were synthesized and used as curing agent for preparing high performance and flame retardancy epoxy resins. The structure of the resin was confirmed with FTIR and elemental analysis. Thermal properties and thermal degradation behaviors of the thermosetted resin was investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The epoxy resins exhibited high glass transition temperature (143–156°C), goof thermal stability (>330°C) and retardation on thermal degradation rates. High char yields (700°C, 52.9%) and high limited oxygen indices (30.6–34.8) were observed, indicating the resins' good flame retardance for the P‐PMFs/CNE cured resins. The developed resin may be used potentially as environmentally preferable products in electronic fields. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3813–3817, 2007     

Curing reaction mechanism and heat resistance properties of hexa‐(4‐carboxyl‐phenoxy)‐cyclotriphosphazene/bisphenol A aniline benzoxazine blends

A blend system of hexa‐(4‐carboxyl‐phenoxy)‐cyclotriphosphazene (HCPCP) and bisphenol A aniline benzoxazine (BA‐a) was prepared, and its curing reaction mechanism and heat resistance properties were studied. The curing reaction mechanism of the blend was explored by differential scanning calorimetry, Fourier transform infrared spectroscopy, and modeling software using model compounds Ar‐COOH and hexachlorocyclotriphosphazene (HCCP). The heat resistance properties of the cured blends were studied by thermogravimetric analysis and dynamic mechanical analysis. The polymerization of benzoxazine was catalyzed by HCPCP through phosphazene ring and acid groups, and phosphazene played a predominant role. Compared with the materials with a single functional group (Ar‐COOH and HCCP), HCPCP containing two functional groups (phosphazene ring and acid) exhibited weaker catalytic effects, mainly due to the high molecular weight of HCPCP obstructing movement and causing steric hindrance. In addition, HCPCP had a positive effect on the thermal stability of polybenzoxazine from 250 to 400 °C. When the HCPCP content reached 3%, the cured blend had the highest glass‐transition temperature (222.2 °C), which is higher by 20 °C than that of cured benzoxazine. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46389.     

Synthesis and characterization of phthalonitrile resins from ortho‐linked aromatic and heterocyclic monomers

This article describes the synthesis and properties of phthalonitrile polymers prepared from three different ortho‐linked monomers, namely 2,2′‐bis(3,4‐dicyanophenoxy)biphenyl, 1,2‐bis(3,4‐dicyanophenoxy)benzene and 2,2′‐bis(3,4‐dicyanophenoxy)‐1,3,4‐oxadiazole. The resins exhibited a low complex viscosity, with a varying range of processing temperatures for all three systems. Thermogravimetric analysis showed that the synthesized polymers exhibited high thermal and thermo‐oxidative stability. The high char yields, which ranged from 64 to 69% at 900 °C under nitrogen atmosphere, and the high glass transition temperatures of the polymers indicated a high crosslinking density in the network structure. Dynamic mechanical measurements demonstrated that the fully cured monomer 2,2′‐bis(3,4‐dicyanophenoxy)‐1,3,4‐oxadiazole exhibited no change in glass transition temperature or in storage modulus up to 500 °C. © 2013 Society of Chemical Industry     

Synthesis and characterization of new cardo poly(ether imide)s derived from 9,9‐bis [4‐(4‐aminophenoxy)phenyl]xanthene

A series of new cardo poly(ether imide)s bearing flexible ether and bulky xanthene pendant groups was prepared from 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene with six commercially available aromatic tetracarboxylic dianhydrides in N,N‐dimethylacetamide (DMAc) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The intermediate poly(amic acid)s had inherent viscosities between 0.83 and 1.28 dL/g, could be cast from DMAc solutions and thermally converted into transparent, flexible, and tough poly(ether imide) films which were further characterized by X‐ray and mechanical analysis. All of the poly(ether imide)s were amorphous and their films exhibited tensile strengths of 89–108 MPa, elongations at break of 7–9%, and initial moduli of 2.12–2.65 GPa. Three poly(ether imide)s derived from 4,4′‐oxydiphthalic anhydride, 4,4′‐sulfonyldiphthalic anhydride, and 2,2‐bis(3,4‐dicarboxyphenyl))hexafluoropropane anhydride, respectively, exhibited excellent solubility in various solvents such as DMAc, N,N‐dimethylformamide, N‐methyl‐2‐pyrrolidinone, pyridine, and even in tetrahydrofuran at room temperature. The resulting poly(ether imide)s with glass transition temperatures between 286 and 335°C had initial decomposition temperatures above 500°C, 10% weight loss temperatures ranging from 551 to 575°C in nitrogen and 547 to 570°C in air, and char yields of 53–64% at 800°C in nitrogen. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Dielectric and thermal behaviors of fluorine‐containing dianhydride‐modified polybenzoxazine: A molecular design flexibility

Fluorine‐containing copolybenzoxazines were successfully prepared by reacting bisphenol‐AF/aniline‐based benzoxazine resin (BAF‐a) with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) in N,N‐dimethylacetamide solvent. The dielectric and thermal properties as well as flexibility of the resulting copolymer films were investigated. The incorporation of fluorine groups into polybenzoxazine was found to substantially decrease the dielectric constant of the resulting copolybenzoxazine to as low as 2.6. The formation of ester linkages between the hydroxyl groups in the poly(BAF‐a) and the carbonyl groups in the 6FDA resulted in substantially enhanced flexibility of the copolybenzoxazines. Moreover, the copolymers showed superior degradation temperature and significant improvement in char yield, up to 464 °C and 56%, respectively. The glass‐transition temperature of the copolybenzoxazines was increased with increasing dianhydride content and exhibited a maximum value of 290 °C at 2.5/1 mole ratio of poly(BAF‐a) to 6FDA. Therefore, the fluorine‐containing dianhydride‐modified polybenzoxazines are appropriate for applications as polymeric films for coatings and as a good electrical insulation material with high thermal resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45204.     

Synthesis and characterization of acetylene‐terminated polybenzoxazines based on polyaralkyl‐phenolic prepolymer

Xylok polybenzoxazine with acetylene group terminals (XPBZAs) were synthesized by the Mannich‐like condensation of Xylok prepolymer, formaldehyde, aminophenylacetylene, and aniline, and their structures were characterized by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR). The curing behavior of XPBZAs was determined by differential scanning calorimetry and FTIR. Thermal behavior and dynamic mechanical properties of the cured XPBZAs were investigated using thermogravimetric analysis and dynamic mechanical analysis. The results showed glass transition temperature (T_g), the thermal stability, and anaerobic char residue of cured XPBZAs increased as the content of acetylene groups increased. POLYM. ENG. SCI., 50:1751–1757, 2010. © 2010 Society of Plastics Engineers     

Synthesis,characterization, and thermal properties of tris (3‐aminophenyl) phosphine oxide‐based nadimide resins

This article describes the synthesis, characterization, and thermal properties of nadimides obtained by reacting endo‐5‐norbornene‐2,3‐dicarboxylic acid anhydride (nadic anhydride) (NA), 4,4′‐oxodiphthalic anhydride (ODA), 1,4,5,8‐naphthalene tetra carboxylic dianhydride (NTDA) in glacial acetic acid/DMF. Structural characterization of the resins was done by elemental analysis, IR, ¹H‐NMR, and ¹³C‐NMR. The DSC scan showed the endothermic transition in the temperature range of 120–270°C. Multistep decomposition was observed in the TG scan of uncured resins in nitrogen atmosphere. Isothermal curing of the resins was done at 250 and 300°C for 1 h in an air atmosphere. These cured resins were stable to (350 ± 30)°C and decomposed in a single step above this temperature. This may be due to the retro Diels Alder (RDA) reaction. The char yield of the resins increased significantly on curing. The char yield was highest for P‐2N resin and this could be due to the presence of rigid skeleton i.e. naphthalene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Phosphorous‐containing epoxy resins from a novel synthesis route

The ? P(O)‐H in 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was used as an active group to react with the carbonyl group in 4,4′‐dihydroxybenzophenone (DHBP) to result a novel phosphorous‐containing biphenol compound (DOPO‐2OH). Phosphorous‐containing epoxy resins were therefore obtained from reacting DOPO‐2OH with epichlorohydrin or with diglycidylether bisphenol A. The synthesized compounds were characterized with FTIR, ¹H and ³¹P NMR, elemental analysis, and epoxide equivalent weight titration to demonstrate the their chemical structures. Cured epoxy resins were prepared via thermal curing the epoxy resins with various curing agents. Thermal analysis results (differential scanning calorimetry and thermogravimetric analysis) revealed that these cured epoxy resins exhibited high glass transition temperatures and high thermal stability. High char yields at 700°C and high LOI (limited oxygen index) values were also found for the cured epoxy resins to imply that the resins were possessing high flame retardancy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1697–1701, 2002     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 9,9‐bis[4‐(4‐amino‐2‐trifluoromethyl‐ phenoxy)phenyl]xanthene

A new trifluoromethylated bis(ether amine) monomer, 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene (BATFPX), was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel fluorinated polyimides were synthesized from BATFPX with various commercially available aromatic tetracarboxylic dianhydrides by one‐step polycondensation in m‐cresol. The resulting polyimides were readily soluble in many organic solvents such as N,N‐dimethylacetamide and tetrahydrofuran, and afforded transparent, flexible and strong films with low moisture absorption (0.28–0.51%), low dielectric constant (2.85–3.26 at 1 MHz) and good optical transparency with UV‐visible absorption cut‐off wavelengths at 352–410 nm. All the polyimides were amorphous and exhibited high thermal stability, with glass transition temperatures of 282–330 °C, 5% weight loss temperatures above 520 °C in nitrogen or air and char yields higher than 55% at 800 °C in nitrogen. Also, these polyimides had good mechanical properties with tensile strengths of 93–118 MPa, elongations at break of 9–16% and initial moduli of 2.07–2.58 GPa. Copyright © 2011 Society of Chemical Industry     

Synthesis and characterization of novel thermally stable and optically active poly(amide‐imide)s derived from N,N′‐(4,4′‐diphthaloyl)‐bis‐L‐leucine diacid and aromatic diamines

A new diacid containing optically active functional groups, N,N′‐(4,4′‐diphthaloyl)‐bis‐L ‐leucine diacid ( 3 ), was synthesized and used in a preparation of a series of poly(amide‐imide)s (PAIs) by direct polycondensation with various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP). All polymers derived from diacid ( 3 ) were highly organosoluble in the solvents like N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, γ‐butyrolactone, cyclohexanone, and chloroform at room temperature or upon heating. Inherent viscosities of the PAIs were found to range between 0.34 and 0.61·dL g^?1. All the PAIs afforded flexible and tough films. The glass‐transition temperatures of these PAIs were recorded between 212 and 237°C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 372 to 393°C and 336–372°C under nitrogen and air, respectively. The polyimide films had a tensile strength in the range of 63–88 MPa and a tensile modulus in the range of 1.2–1.7 GPa. Optically active PAIs exhibited specific rotations in the range of ?10.58° to ?38.70°. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

A novel and facile method for the synthesis of octa(aminophenyl)silsesquioxane and its nanocomposites with bismaleimide‐diamine resin

Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octa(nitrophenyl)silsesquioxane (ONPS) by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent with a yield of around 86%. The product was characterized by FTIR, GPC, ¹H NMR, ²⁹Si NMR, and XRD. It was found that the time period for preparation of ONPS from octaphenylsilsesquioxane could be considerably shortened, reaching the complete nitration and avoiding double nitration of the aromatic rings. The polyimides were prepared by the reaction of N,N′‐bismaleimido‐4,4′‐diphenylmethane with OAPS and 4,4′‐diamino‐diphenyl ether. The structure of resulting organic–inorganic hybrid nanocomposites was characterized by XRD and FTIR. The decomposition temperature and char yield of resulting materials increased with increasing OAPS loading. The DSC data showed that the glass transition temperature of nanocomposite was enhanced by 36°C with the content of OAPS around 15 wt %. As the feed amount of OAPS increased further, the decrease in T_g's could be observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1004–1010, 2007     

A novel polybenzoxazine containing styrylpyridine structure via the Knoevenagel reaction

In this article, a kind of styrylpyridine‐containing polybenzoxazine was obtained via the Knoevenagel reaction between benzaldehyde and methylpyridine groups. The benzoxazine monomer (MPBC) containing the benzaldehyde and methylpyridine groups was synthesized firstly and its structure was characterized by Fourier transform infrared (FTIR) spectra, ¹H NMR and ¹³C NMR. With the aid of differential scanning calorimetry, FTIR, and photoluminescent tests, the interesting curing behaviors were probed. The results showed that the ring‐opening polymerization occurred at lower temperature, and the Knoevenagel reaction further took place at elevated temperature. The amine and phenol moieties were bonded together to form the styrylpyridine structure. Due to these special crosslinking structures, the corresponding polybenzoxazine exhibited excellent thermal stability, and had a special high char yield of 74.5%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40823.     

Synthesis and characterization of homo‐ and copolymers of 3‐(2‐cyano ethoxy)methyl‐ and 3‐[methoxy(triethylenoxy)]methyl‐3′‐methyl‐oxetane

Two oxetane‐derived monomers 3‐(2‐cyanoethoxy)methyl‐ and 3‐(methoxy(triethylenoxy)) methyl‐3′‐methyloxetane were prepared from the reaction of 3‐methyl‐3′‐hydroxymethyloxetane with acrylonitrile and triethylene glycol monomethyl ether, respectively. Their homo‐ and copolyethers were synthesized with BF₃· Et₂O/1,4‐butanediol and trifluoromethane sulfonic acid as initiator through cationic ring‐opening polymerization. The structure of the polymers was characterized by FTIR and¹H NMR. The ratio of two repeating units incorporated into the copolymers is well consistent with the feed ratio. Regarding glass transition temperature (T_g), the DSC data imply that the resulting copolymers have a lower T_g than pure poly(ethylene oxide). Moreover, the TGA measurements reveal that they possess in general a high heat decomposition temperature. The ion conductivity of a sample (P‐AN 20) is 1.07 × 10^?5 S cm^?1 at room temperature and 2.79 × 10^?4 S cm^?1 at 80 °C, thus presenting the potential to meet the practical requirement of lithium ion batteries for polymer electrolytes. Copyright © 2005 Society of Chemical Industry     

Novel phenyl acetylene terminated poly(carborane‐silane): Synthesis,characterization, and thermal property

Phenyl acetylene terminated poly(carborane‐silanec) (PACS) was synthesized by the couple reaction of methyldichlorosilane with 1,7‐dilithio‐m‐carborane and lithium phenylacetylide. The structure was characterized using FTIR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, and gel permeation chromatography. PACS exhibits solubility in common organic solvents. Thermal and oxidative properties were evaluated by thermogravimetric analysis (TGA). Thermoset exhibits extremely thermal and oxidative property and TGA curves show that the temperature of 5% weight loss (Td₅) is 762°C and char yield at 800°C is 94.2% in nitrogen. In air, surprisingly, both Td₅ and char yield at 800°C show slight increase, which is greater than 800°C and 95.6%, respectively. After pyrolysis, the char has no additional weight loss up to 800°C in air. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2498–2503, 2007     

An m‐phenylenediamine‐based benzoxazine with favorable processability and its high‐performance thermoset

A novel aromatic diamine‐based benzoxazine (P‐mPDA) is successfully synthesized from m‐phenylenediamine (m‐PDA), 2‐hydroxybenzaldehyde, and formaldehyde. The polymerization behavior of P‐mPDA and the properties of its thermoset are studied. The results indicate that P‐mPDA owns favorable processability including low polymerization temperature, low liquefying temperature, and wide processing window. Even lower polymerization temperature (polymerization onset temperature as low as 80 °C) can be achieved by the promotion of catalysts. The ring‐opening polymerization of P‐mPDA first generates polybenzoxazine with N, O‐acetal‐type structure and arylamine Mannich‐type structure, following which rearrangement from N, O‐acetal‐type structure to phenolic Mannich‐type structure proceeds at elevated temperature. Furthermore, the polymerized P‐mPDA shows outstanding performance such as extremely high glass transition temperature (T_g) of 280 °C, high char yield above 53% at 800 °C under nitrogen and excellent mechanical property. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43368.     

Transparent photo‐curable co‐polyacrylate/silica nanocomposites prepared by sol‐gel process

This work prepared the highly transparent photo‐curable co‐polyacrylate/silica nanocomposites by using sol‐gel process. The FTIR and ¹³C NMR analyses indicated that during the sol‐gel process, the hybrid precursors transform into composites containing nanometer‐scale silica particles and crosslinked esters/anhydrides. Transmission electron microscopy (TEM) revealed that the silica particles within the average size of 11.5 nm uniformly distributed in the nanocomposite specimen containing about 10 wt % of Si. The nanocomposite specimens exhibited satisfactory thermal stability that they had 5% weight loss decomposition temperatures higher than 150°C and coefficient of thermal expansion (CTE) less than 35 ppm/°C. Analysis via derivative thermogravimetry (DTG) indicated that the crosslinked esters/anhydrides might influence the thermal stability of nanocomposite samples. The UV‐visible spectroscopy indicated that the nanocomposite resins possess transmittance higher than 80% in visible light region. Permeability test revealed a higher moisture permeation resistance for nanocomposite samples, which indicated that the implantation of nano‐scale silica particles in polymer matrix forms effective barrier to moisture penetration. Adhesion test of nanocomposite samples on glass substrate showed at least twofold improvement of adhesion strength compared with oligomer. This evidenced that the silica and the hydrophilic segments in nanocomposite resins might form interchains hydrogen bonds with the ? OH groups on the surface of glass so the substantial enhancement of adhesion strength could be achieved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007