Methacrylate/acrylate terminated derivatives of diglycidyl hexahydrophthalate: Synthesis,structural, and thermal characterization

Mono‐ or di(meth)acrylate‐terminated derivatives of diglycidyl hexahydrophthalate (ER) were prepared by reacting 1 : 1 or 1 : 2M ratio of ER and methacrylic acid or acrylic acid. These vinyl ester (VE) resins were characterized by determining epoxy equivalent weight, acid number, and molecular weight by gel permeation chromatography. Structural characterization was done by FTIR and ¹H NMR spectroscopy. In the ¹H NMR spectra of acrylate‐terminated VE resins, three proton resonance signals were observed in the region 5.8–6.4 ppm due to vinyl group while in methacrylate‐terminated VE resins only two proton resonance signals due to vinylidene protons were observed at 5.6–6.1 ppm. The Brookfield viscosity (room temperature (25 ± 2)°C) of these resins diluted with varying amounts of MMA was determined at 20 rpm. Curing behavior was monitored by determination of gel time and differential scanning calorimetry. An exothermic transition was observed in the DSC scans in the temperature range of (81–150)°C. Isothermal curing of MMA‐diluted VE resins containing AIBN as an initiator was done at 60°C for 2 h in N₂ atmosphere, and then heating for another 2 h in static air atmosphere. Thermal stability of isothermally cured resins in N₂ atmosphere was evaluated by thermogravimetric analysis. All cured resins decomposed above 310°C in single step. Thermal stability of the cured resins having acrylate end caps was marginally higher than the resins having methacrylate end groups. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Synthesis,characterization, and thermal properties of cyanate esters with azo linkages

A series of azo functionalized diols were synthesized through diazotization which involves the reaction of amine with phenol and 2,6‐dimethyl phenol. Four different amines have been used to prepare five bisphenols. These bisphenols were converted to their corresponding cyanate esters by treatment with cyanogen bromide (BrCN) in the presence of triethylamine (Et₃N). The chemical structures of the prepared compounds were characterized with Fourier Transform Infrared, ¹H‐NMR, ¹³C‐NMR spectroscopy, and elemental analysis. Dynamic curing behavior was investigated using differential scanning calorimetry. The maximum curing temperature of these cyanate esters are in the range of (186–208°C). T_g values of the polycyanurate networks are in the range of 245–276°C. The thermal properties of cured cyanate ester were studied at a heating rate of 10°C min^?1 in N₂ atmosphere. The polymers showed excellent thermal stability (T₁₀ was found to be in the range 405–438°C) and the percentage of char yield at 800°C were found to be 30–49. The flame retardancy of the cyanate ester resins have been studied using limited oxygen index value which is in the range of 29.5–37.1 at 800°C. POLYM. ENG. SCI., 55:47–53, 2015. © 2014 Society of Plastics Engineers     

Synthesis and properties of silicon-containing bismaleimide resins

Two novel bismaleimide (BMI) monomers containing silicon atom in the structure, i.e., bis[4-(4-maleimidophenylcarbonyloxy)phenyl]dimethylsilane (BMI-SiE1) and bis[4-(4-maleimidophenyloxycarbonyl)phenyl]dimethylsilane (BMI-SiE2), were designed, synthesized, and polymerized with and without the use of diamine as comonomers to yield novel silicon-containing BMI resins. Both monomers obtained are readily soluble in organic solvents, such as chloroform and N, N-dimethylformamide. Differential scanning calorimetry and thermogravimetric analysis investigation of these two monomers indicated a high polymerization temperature (T_p > 240°C) and a good thermal and thermo-oxidative stability of cured BMI resins. The onset temperature for 5% weight loss was found to be above 450°C in nitrogen and above 400°C in the air. Polymerization of BMI-SiE1 and BMI-SiE2 with 4,4′-diaminodiphenylether (DPE) yielded a series of polyaspartimides that had good solubility and could be thermally cured at 250°C. TGA investigations of the cured diamine-modified BMI resins showed onset of degradation temperatures (T_ds) in the range of 344–360°C in nitrogen and 332–360°C in the air. Composites based on the cured diamine-modified BMI resins and glass cloth were prepared and characterized for their dynamic mechanical properties. All the composites showed high glass transition temperatures (e.g., >190°C) and high bending modulus in the range of 1000–2700 MPa. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,characterization, and properties of silylene–acetylene preceramic polymers

A series of silylene–acetylene preceramic polymers 3a–e were synthesized by polycondensation reaction of dilithioacetylene with dichlorosilane (H₂SiCl₂) or/and methyldichlorosilane (MeSiHCl₂). Their structures were confirmed by infrared spectra (IR), and ¹H and ²⁹Si NMR spectroscopies. Differential scanning calorimetry (DSC) diagrams show exotherms centered at 200 to 233°C temperature range, attributed to crosslinking reaction of the acetylene and Si? H groups. After thermal treatment, the obtained thermosets 4a–e possess excellent thermal stability. Thermogravimetric analysis (TGA) under nitrogen show the T_d5s (temperature of 5% weight loss) for all the thermosets are above 600°C, and the overall char yields are between 95.62% and 89.67% at 900°C. After pyrolysis at 1200°C, the obtained ceramic residues 5a–e exhibit good thermo‐oxidative stability with final weight retention between 98.76% and 91.66% at 900°C under air. In particular, perhydroploy(silylene)ethynylene 3a , which has the highest Si/C ratio in silylene–acetylene polymers, has the highest char yield, and the derived ceramic material 5a displays the best thermo‐oxidative stability. Based on Scanning electron microscopy and its associated energy‐dispersive X‐ray microanalysis (SEM EDX) and ¹³C magic angle spinning nuclear magnetic resonance (MAS NMR) analysis, ceramic 5a contains the highest SiC content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Organic/inorganic hybrid bismaleimide resin with octa(aminophenyl)silsesquioxane

Octa(aminophenyl)silsesquioxane (OAPS) was prepared in two steps by the nitration of octaphenylsilsesquioxane (OPS) in fuming nitric acid to form octa(nitrophenyl)silsesquioxane (ONPS), followed by the mild reduction of ONPS with Pd/C as a catalyst. OPS, ONPS and OAPS were characterized by FTIR, ¹H NMR, and ²⁹Si NMR techniques. Modification of a bismaleimide (BMI) resin with OAPS and dipropargyl ether of bisphenol A (DPBPA) was investigated. The modified resins, OAPS/DPBPA/BMI, were characterized with DSC, FTIR and rheology analyses. The results showed that the modified resins have good processability. The DMA results indicated that the glass transition temperature (T_g) of the cured OAPS/DPBPA/BMI hybrid resins reached 350°C. The decomposition temperature (T_d5) of the cured resins decreased but the char yield (Y_c, 800°C) increased as the OAPS loading increased, especially in air. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Synthesis and characterization of dicyanate monomers containing methylene spacers

The bisphenols containing methylene spacer were prepared by treating eugenol/2‐allyl phenol with 2,6‐dimethyl phenol/guiacol/o‐cresol in the presence of AlCl₃. All the bisphenols were converted to their respective cyanate esters by treating with CNBr. The structural confirmation was done by FTIR, ¹H NMR, ¹³C NMR spectral methods, and elemental analysis. Thermal characterization was done by DSC and TGA. DSC transition shows that the T_g is in the range of 208–239°C. The T_g is highest for the cyanate ester Cy(b) with symmetric structure. The T_g of the cured network depends on the length and symmetry of the monomer, T_g being higher for shorter and the para‐substituted monomers. The T₁₀ values are in the range of 364–381°C. The char yield is in the range of 47–53%. From the char yield, the limiting oxygen index (LOI) value was determined, which is used to confirm the flame retardancy of the cyanate ester resins. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,characterization, and curing of unsaturated polyamides derived from 2,6-di(4-carboxystyryl)pyridine and 2,6-bis(4-carboxybenzylidene) cyclohexanone

Two new series of heat-curable polyamides were prepared utilizing the unsaturated dicarboxylic acids 2,6-di(4-carboxystyryl)pyridine (DCSP) and 2,6-bis(4-carboxybenzylidene)cyclohexanone (BCBC) as starting materials. They were prepared from the condensation of 4-carboxybenzaldehyde with a half molar amount of 2,6-dimethylpyridine or cyclohexanone, respectively. The dicarboxylic acids reacted with various aromatic diamines, utilizing triphenyl phosphite and pyridine as condensing agents, to yield polyamides. In addition, two model diamides were prepared by condensing the dicarboxylic acids with aniline. Characterization of starting materials, polyamides, and model compounds was accomplished by IR and ¹H–NMR spectroscopy. The curing behavior of polyamides was investigated by DTA. Upon heat-curing, the unsaturated polyamides were crosslinked through their olefinic bonds to afford insoluble, heat-resistant resins. The thermal stability of the resins was evaluated by TGA and isothermal gravimetric analysis (IGA). The cured resins were stable up to 310–322°C in N₂ or air and afforded anaerobic char yield of 57–69% at 800°C.     

Preparation of melamine–formaldehyde resin grafted by (3-aminopropyl) triethoxysilane for high-performance hydrophobic materials

Aiming at meeting the specific market demands and expanding the downstream application of melamine–formaldehyde (MF) resins, a series of (3-aminopropyl) triethoxysilane (APTES) grafted MF (MF-Si) resins were synthesized via an effective method that minimized the hydrolysis of APTES and overcame the polarity discrepancy of APTES with MF resin matrix. The structure of MF-Si resins was characterized by FTIR spectroscopy, Raman spectroscopy, ¹H nuclear magnetic resonance (NMR), and solid state ¹³C NMR. It was found that APTES moieties in MF-Si materials afforded increased hydrophobicity, water resistance, and the thermal stability was not affected. With the increasing amount of APTES, the water contact angle of MF-Si films increased from 70.56 to 105.92°and the surface free energy decreased from 46.8 to 23.5 mN/m. The temperature of maximum weight loss rate (T_dmax) of MF-Si materials decreased slightly from 371.15 to 353.70 °C and the ultimate residual weight of MF-Si materials increased from 12.51 to 30.04% at 800 °C under N₂. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48664.     

Studies of fluorine‐containing bismaleimide resins part I: Synthesis and characteristics of model compounds

A series of fluorine‐containing bismaleimide (FBMI) monomers are synthesized by a 3‐step reaction for using as the applications of low‐k materials. The synthesized FBMI monomers are characterized by the ¹H, ¹³C, ¹⁹F nuclear magnetic resonance (NMR) spectroscopy and element analysis. These FBMI monomers react with free radical initiator or self‐cure to prepare FBMI‐polymers. All the self‐curing FBMI resins have the glass transition temperatures (T_g) in the range of 128–141°C and show the 5% weight loss temperatures (T_5%) of 235–293°C in nitrogen atmosphere. The higher heat resistance of self‐curing FBMI resin relative to FBMI‐homopolymer is due to its higher crosslinking density. The FBMI resins exhibit improved dielectric properties as compared with commercial bismaleimide (BMI) resins with the dielectric constants (D_k) lower than 2.49, which is related to the low polarizability of the C? F bond and the large free volume of CF₃ groups in the polymers. Besides, the flame retardancy of all these FBMI resins could be enhanced via the introduction of Br‐atom. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of new cardo poly(bisbenzothiazole)s from 1,1‐bis(4‐amino‐3‐mercaptophenyl)‐4‐tert‐butylcyclohexane dihydrochloride

A new monomer 1,1‐bis(4‐amino‐3‐mercaptophenyl)‐4‐tert‐butylcyclohexane dihydrochloride, bearing the bulky pendant 4‐tert‐butylcyclohexylidene group, was synthesized from 4‐tert‐butylcyclohexanone in three steps. Its chemical structure was characterized by ¹H NMR, ¹³C NMR, MS, FTIR, and EA. Aromatic poly(bisbenzothiazole)s (PBTs V) were prepared from the new monomer and five aromatic dicarboxylic acids by direct polycondensation. The inherent viscosities were in the range of 0.63–2.17 dL/g. These polymers exhibited good solubility and thermal stability. Most of the prepared PBTs V were soluble in various polar solvents. Thermogravimetric analysis showed the decomposition temperatures at 10% weight loss that were in the range of 495–534°C in nitrogen. All the PBTs V, characterized by X‐ray diffraction, were amorphous. The UV absorption spectra of PBTs V showed a range of λ_max from 334 to 394 nm. All the PBTs V prepared had evident fluorescence emission peaks, ranging from 423 to 475 nm with different intensity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2000–2008, 2006     

Preparation,solubility and thermal behaviour of new bismaleimides containing silicone linkages

A series of new bismaleimides containing silicone linkages have been prepared via Diels–Alder reaction of bismaleimides containing silicone and bisfurans containing silicone; their molecular structures have been characterized by FTIR, NMR and elemental analysis. The solubility of the prepared bismaleimides was tested in six types of solvent of different boiling point and polarity, and their curing temperatures were determined by DSC. The thermal-oxidative stability of the cured networks was investigated by TGA and their glass transition temperatures were measured by DSC, revealing that the bismaleimides are soluble in low boiling point solvents and their curing temperatures are in the range 206–285°C. The DSC and TGA traces of cured networks show that the glass transition temperatures are in the range 287–331°C and that these resins are stable up to 353–384°C. © 1999 Society of Chemical Industry     

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     

Preparation and properties of bismaleimide resins of aromatic sulfone ether diamine

Aromatic sulfone ether diamine, bis[4-(4-aminophenoxy)phenyl]-sulfone (SED), was prepared by the nucleophilic aromatic substitution of 4,4′-dichlorodiphenylsulphone by p-aminophenolate. The reaction was conducted in the presence of excess potassium carbonate as a weak base, toluene as the dehydrating agent and N-methylpyrrolidone as the dipolar aprotic solvent. SED showed good solubility in common organic solvents, such as dioxan, tetrahydrofuran, butanone and acetone. SED was reacted with maleic anhydride to obtain aromatic sulfone ether bismaleimide, bis[4-(4-maleimidophenoxy)phenyl]-sulfone (SEM). The compounds were characterized by FTIR and ¹H NMR analysis. Furthermore, copolymer resins of SED with 4,4′-bismaleimidodiphenyl methane (BMI) and SEM were prepared. After curing, crosslinked resins with better thermal stability resulted. The temperature at maximum rate of weight loss (T_max) and the heat-resistant temperature index (T_i) in air were found to be 426°C, 208°C and 579°C, 221°C for BMI/SED and SEM/SED resins, respectively. Compared with the corresponding 4,4′-diaminodiphenyl methane (DDM) system, BMI/SED and SEM/SED showed a slight decrease in T_max and T_i SED-modified BMI/amine resin based glass cloth laminates for printed circuit boards showed higher mechanical properties than those of the corresponding unmodified system. With SED instead of the original amine component in 3–5% weight fraction, the tensile strength, flexural strength and impact strength of the laminates increased markedly. Meanwhile, the stripping strength and weld resistance were also improved by the addition of SED.     

Synthesis and thermal property of boron–silicon– acetylene hybrid polymer

Inorganic–organic boron–silicon–acetylene hybrid polymer (PABS) was prepared by the polycondensation reaction between phenylboric acid and diphenyldichlorosilane and then terminated by phenylacetylene. The structure was characterized by using FTIR, ¹³C‐NMR, ¹H‐NMR, and GPC. PABS was a kind of resin exhibited high viscous at room temperature and good solubility in common organic solvents. The thermal and oxidative properties were evaluated by DSC and TGA. Exothermal peak at 370°C observed by DSC was attributed to reaction of the acetylene units. PABS showed excellent thermal and oxidative stability, and TGA exhibited the temperature of 5% weight loss (Td₅) was 625°C and char yield at 900°C was 90.0% in nitrogen. Surprisingly, both Td₅ and char yield at 900°C showed slightly increase in air, which was 638°C and 90.9%, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of novel aromatic polyamides bearing CF3, quinoxaline‐anthraquinone pendants: Study of photophysical and electrochemical properties by using nanocomposite electrode paste

A new aromatic diamine, 2,3‐bis(4‐(4‐amino‐2‐(trifluoromethyl) phenoxy)phenyl)naphtho[2,3‐f]quinoxaline‐7,12‐dione, was synthesized and fully characterized by using FTIR, ¹H and ¹³C NMR, DEPT technique, and elemental analysis. A series of novel fluorescent anthraquinone‐quinoxaline containing polyamides (PAs) with inherent viscosities of 0.39–0.62 dL/g was prepared by direct polycondensation of the diamine with various dicarboxylic acids. These PAs were readily soluble in many polar aprotic organic solvents and could be solution‐cast into tough and flexible films. The PAs exhibited glass transition temperatures (T_g)s between 230 and 323°C, and 10% weight loss temperatures in the range of 362–433°C in N₂. All of the PAs have fluorescence emission in solution and in solid state with maxima around 452–510 nm and with the quantum yields in the range of 6–17%. Also, cyclic voltammetry (CV) method was used to study the electrochemical oxidation behavior of these polymers at the surface of a modified multiwalled carbon nanotube (MWCNT)s glassy electrode. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Novel heat resistant methyl‐tri(phenylethynyl)silane resin: Synthesis,characterization and thermal properties

Methyl‐tri(phenylethynyl)silane (MTPES) was successfully synthesized by the reaction of lithium phenylacetylide with methyltrichlorosilane. The structure was characterized by HRMS, FTIR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, and elementary analysis. Thermal cure process was monitored by DSC, DMA, and FTIR. MTPES was heated to free flowing liquid around 130°C and thermally polymerized at 327–377°C to form thermoset. Thermal and oxidative properties were evaluated by TGA analysis. Thermoset exhibits extremely high heat‐resistance and TGA curve in nitrogen shows the temperature of 5% weight loss (Td₅) of 695°C and total weight loss at 800°C of 7.1%. TGA shows a high Td₅ of 565°C even in air, although the total weight loss at 800°C was 56.1% of the initial weight, much higher than that in nitrogen. The high heat resistance of MTPES was ascribed to crosslinking reaction concerning ethynyl groups. Aging studies performed at elevated temperatures in air on a thermoset showed that MTPES is oxidatively stable to 300°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2488–2492, 2006     

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     

Investigation of novel polytriazole resins

2,4,6-Tri(4-propargyloxy-phenyl)pyridine(POPP) was made from 2,4,6-tri (4-hydroxyphenyl)pyridine(HPP) and propargyl bromide. The chemical structures of POPP and HPP were well characterized by means of FTIR, ¹H-NMR, ¹³C-NMR, and elemental analysis. Novel polytriazole resins (P-PTA resins) were prepared from POPP and azide compounds via 1, 3-dipolar cycloaddition reaction and characterized by solubility, FTIR, DSC, and TGA analyses. The P-PTA resins show good solubility in common solvents. The resins could be cured at 80 °C. The glass transition temperature (T_g) and the 5% weight loss temperature (T_d5) of the cured P-PTA-33 resin arrive at 310 and 365 °C in nitrogen atmosphere, respectively.     

Synthesis,characterization, and reactivity ratios of copolymers derived from 4‐nitrophenyl acrylate and n‐butyl methacrylate

Free‐radical copolymerization of 4‐nitrophenyl acrylate (NPA) with n‐butyl methacrylate (BMA) was carried out using benzoyl peroxide as an initiator. Seven different mole ratios of NPA and BMA were chosen for this study. The copolymers were characterized by IR, ¹H‐NMR, and ¹³C‐NMR spectral studies. The molecular weights of the copolymers were determined by gel permeation chromatography and the weight‐average (M _w) and the number‐average (M _n) molecular weights of these systems lie in the range of 4.3–5.3 × 10⁴ and 2.6–3.0 × 10⁴, respectively. The reactivity ratios of the monomers in the copolymer were evaluated by Fineman–Ross, Kelen–Tudos, and extended Kelen–Tudos methods. The product of r₁, r₂ lies in the range of 0.734–0.800, which suggests a random arrangement of monomers in the copolymer chain. Thermal decomposition of the polymers occurred in two stages in the temperature range of 165–505°C and the glass transition temperature (T_g) of one of the systems was 97.2°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1817–1824, 2003     

Thermal behavior and properties of naphthalene containing bismaleimide–triazine resins

A series of bismaleimid·triazine (BT) resins were prepared from various dicyanate esters and 2,7-bis(4-maleimidophenoxy)naphthalene (BMPN), which contains a naphthalene group and an aryl ether linkage in the backbone. Their curing behaviors were characterized by differential scanning calorimetry. The exotherm temperature and polymerization reactivity were strongly affected by the chemical structure of the various dicyanate ester monomer. Thermal behaviors were investigated by thermogravimetric analyses and dynamic mechanical analyses. The glass transition temperatures (T_g) of these cured resins with bismaleimide/dicyanate ester at the 1/2 molar ratio were in the range of 250–322°C, and exhibited excellent thermal stability up to 400°C in nitrogen. These results provided a structure–properties relationship for the cured bismaleimid·triazine resins. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1199–1207, 1998