Farong Huang

Characterization of modified bismaleimide resin

A new high-temperature resin system based on methylene dianiline bismaleimide (MDA-BMI) chemistry is studied. This is a two-component resin system which is modified by 2,2′-methylene-bis[4-methyl-6-(2-propenyl)] phenol (MBMPP) and has excellent thermal mechanical properties and good toughness characteristics. This paper discusses in detail some of the characteristics of the prepolymer by reacting the two components in addition to the cured systems properties. The prepolymer has very good stability at 100–120°C with very minimal molecular weight increase. The reaction order for curing prepolymer is almost 1. The activation energy of the curing reaction is 74.12 KJ/mol. The flexural strength and modulus of the cured modified MDA-BMI and their retention at 250°C are 124 and 3774.6 MPa and 69 and 78%, respectively.

o-Carborane-Containing Poly(siloxane-arylacetylene)s With Thermal and Thermo-Oxidative Stabilities

A series of poly(siloxane-arylacetylene)s with o-carborane in the backbone (CB-PSOA)s were prepared by the coupling reaction between poly(siloxane-arylacetylene) (PSOA) and decaborane (B10H14) in the presence of CH3CN. CB-PSOAs were characterized by Fourier-transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS). The results show that the average amount of carborane units in a CB-PSOA chain could be raised when the molar ratio of B10H14 to PSOA is increased from 0.6 to 2.4. The crosslinking reaction could be carried on at above 140°C for CB-PSOAs. The CB-PSOA thermosets show excellent thermo oxidative stability with over 85% residue yield at 1000°C in air.

Synthesis of novel imide-functionalized fluorinated benzoxazines and properties of their thermosets

In this study, two novel imide-functionalized fluorinated benzoxazines, N,N′-bis(N-phenylacetylene-3,4-dihydro-2H-1,3-benzoxazinyl)-(4,4′-hexafluoroisopropylidene)bisphthalimide (6FIBZ-apa) and N,N′-bis(N-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl)-(4,4′-hexafluoroisopropylidene)bisphthalimide (6FIBZ-a), were successfully synthesized. The structures of the benzoxazines were confirmed by Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. The novel benzoxazines were easily dissolved in common organic solvents. The differential scanning calorimetric curve of 6FIBZ-apa showed only a single exothermic peak since oxazine ring-opening and acetylene addition polymerization occurred simultaneously in the same temperature range. The introduction of rigid and thermally stable imide moiety led to rigid molecular structure, thus resulting in an increase in the glass transition temperature and improvement in thermal stability. The thermal properties were further improved significantly by the incorporation of cross-linkable acetylene groups to increase the cross-linking density as evidenced by thermogravimetric analysis.

A novel polytriazole-based organogel formed by the effects of copper ions

A novel organogel in dimethyl formamide or dimethyl sulphoxide (DMF or DMSO), named GelT, was prepared by Cu(I)-catalyzed “click” reaction between diazide and dipropargyl bisphenol A. The action between copper ions and triazole rings was confirmed to be the mechanism of formation of the gel.

Synthesis and Characterization of Poly[(methylsilyleneethynylenephenyleneethynylene)s-co-decamethylpentasiloxane]

Poly[(methylsilyleneethynylenephenyleneethynylene)s-co-decamethylpentasiloxane] was synthesized by polycondensation reaction of di-Grignard reagent of diethynylbenzene with 1,9-dichlorodecamethylpentasiloxane and dichloromethylsilane. The copolymer is a liquid and soluble in common organic solvent at room temperature. The copolymer was characterized by FTIR, 1H-NMR, rheological analysis, and differential scanning calorimetry. The results show that the copolymer exhibits good processability and cures at about 170°C. The copolymer can be thermally cured to produce highly crosslinked copolymer. The thermal stability of the cured copolymer was measured by thermogravimetric analysis. The degradation temperature at 5% weight loss is 591°C and the residue yield at 1000°C is 86% in N2. Black, hard, and glassy ceramic was produced when the cured copolymer was heated above 1450°C under argon. The ceramic has high thermooxidative stability.

Novel Functional Polytriazole Elastomer with Thermal Stability and Adjustable Mechanical Properties

We proposed a novel functional polytriazole elastomer (PTE) with thermal stability and adjustable mechanical properties in this article. Attributed to the click chemistry utilized here, the bulk polymerization procedure was conducted efficiently at an amiable temperature. The novel elastomer was considered to be a promising elastomer with low glass transition temperature (Tg < 0°C) and excellent thermal stability (Td5 > 340°C) according to the thermal analysis results. In addition, tensile strength of PTE which ranged from 3.25MPa to 9.49MPa was easily adjusted by controlling the proportion of raw material used in the reaction.

Preparation and properties of silicon-containing arylacetylene resin/benzoxazines blends

A series of aniline-based bifunctional benzoxazines (BZs) were synthesized using solventless or solvent method via the Mannich condensation reactions. The chemical structures of these BZs were confirmed using Fourier-transform infrared and proton-nuclear magnetic resonance spectroscopies. The polymer blends were prepared by mixing silicon-containing arylacetylene (poly(dimethylsilyleneethynylenephenyleneethynylene) (PSA)) resin with BZ in weight ratios at 110°C until a homogeneous viscosity liquid was obtained. The resultant blends were characterized by solubility tests, rheological analyses, differential scanning calorimetry, dynamic mechanical analyses and thermogravimetric analyses. The good solubility and low melt viscosity of the blends indicated excellent processability. The curing reactions resulted in the formation of interpenetrating polymer networks. The cured blends exhibited high glass transition temperatures (T g s) and thermal stabilities. The compressive strength and flexural strength of the blend casts improved when compared with pristine PSA.

Synthesis and characterization of a new series of rigid polytriazole resins

A novel series of polytriazole resins were synthesized by using aromatic diazides and N,N,N′,N′-tetrapropargyl-p,p′-diaminodiphenylmethane (TPDDM) as raw materials. The chemical structures of the resins were characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance. Rheological behavior indicates that the resins can be processed in a low-temperature region, and some of them have good solubilities in common organic solvents. Differential scanning calorimetry and FTIR results demonstrated that the polytriazole resins can be cured at 70 °C. The glass transition temperature (T g) of cured resins increased with the increase in rigidity of diazide units in polymer chains and reaches up to 328 °C.

Synthesis and properties of a novel poly(diethynylbenzene-siloxane) resin

A novel kind of resin poly(diethynylbenzene-siloxane) was synthesized. The resin was easily processable at room temperature and thermally polymerized above 180 °C to form a heat-resistant thermoset. The progress and the nature of polymerization reaction were studied by Fourier transform Infrared spectrometry and differential scanning calorimetry. The conversion of the resin to a highly cross-linked thermoset was discussed. The cross-linked resin exhibited high thermal stability. The sintered product of the crosslinked resin above 1450 °C was analyzed by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectrometry.

Synthesis and Characterization of a Novel Thermostable Polyether-Based Elastomeric Polytriazole via Click Reaction

We report the first synthesis and characterization of a novel thermostable polyether-based elastomeric polytriazole (EPTA) via click reaction. The EPTAs structure was confirmed by proton NMR characterization. The low glass transition temperatures (Tg < 0°C) of EPTAs ensure the product in elastomeric state at room temperature. The high 5% weight loss thermal decomposition temperatures (> 300°C) compared to other elastomeric polymers are the prominent property of the EPTAs. The influence of molecular weight of azide-terminated monomers and structures of dipropargyl ether monomers on the Tg and Td5 of EPTAs were studied.