Synthesis and characterization of ureido-containing MQ silicone resin

Abstract

Ureido-containing MQ silicone resin (U-MTQ) was synthesized by the hydrolysis and co-condensation reaction of ethyl silicate, ureido silane, hexamethyldisiloxane, and divinyltetramethyldisiloxane under the catalysis of hydrochloric acid. U-MTQ was characterized by FT-IR, ¹H-NMR, ²⁹Si-NMR, GPC and TGA. The influences of M/Q molar ratio and hydrochloric acid content on the yield and structure of U-MTQ were investigated. The results showed that the M/Q molar ratio of the product calculated from the ²⁹Si-NMR spectrum was much smaller than that in the feed. As M/Q molar ratio in the feed increased, the molecular weight and its distribution index of U-MTQ decreased, and Si-OH content of U-MTQ also decreased, while the structural regularity of U-MTQ was enhanced. With HCl content increasing, the molecular weight and its distribution index of U-MTQ decreased, but the Si–OH content and structural regularity increased. Meanwhile, the yield first increased and then decreased, and reached the highest value of 71.9% when HCl content was 2.10%. Compared with MQ, the onset weight loss temperature of U-MTQ decreased from 237?°C to 158?°C, and the residue at 900?°C increased from 3.5% to 29.5%.     

Synthesis of conjugated polymers possessing diketopyrrolopyrrole units bearing phenyl,pyridyl, and thiazolyl groups by direct arylation polycondensation: Effects of aromatic groups in DPP on physical properties

Conjugated polymers containing phenyl‐, pyridyl‐, and thiazolyl‐flanked diketopyrrolopyrrole (DPP) were synthesized by direct arylation polycondensation of 3,4‐ethylenedioxythiophene derivatives and dibrominated DPP‐based monomers, in order to probe the effects of the aromatic groups in the DPP units on the absorption property, energy level, and crystallinity. A polymer possessing thiazolyl‐flanked DPP units was found to display long‐wavelength absorption properties and higher crystallinity than the polymers bearing phenyl‐ and pyridyl‐flanked DPP units. These features of the thiazolyl‐based polymer were afforded by its coplanar structure of the main chain. The synthesized polymers showed semiconducting properties in organic field effect transistors and organic photovoltaics. Direct arylation polycondensation is an efficient synthetic method that affords a series of DPP‐based polymers in a simple fashion and, thus, helping in a comprehensive understanding on the relationship between the aromatic groups in DPP units and their physical properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2337–2345     

Synthesis, characterization and evaluation of sulfonic resins as catalysts

Ion-exchange resins have been often used as catalysts especially those based on styrene-divinylbenzene copolymers with sulfonic acid groups in the aromatic rings of polymer chains. That is due to the advantages of heterogenous catalysis over the homogeneous acid catalysis. Moreover, resin catalysts can often lead to high selectivity in organic reactions due to the matrix effects. Therefore, the study of copolymers synthesis conditions to determine the type of polymer structure produced as well as the characterization of sulfonic resins obtained thereof are of great interest. The current paper describes the synthesis, characterization and evaluation as catalysts of sulfonic resins derived from polymer supports synthesized by aqueous suspension polymerization of styrene and divinylbenzene. The reaction conditions were varied and polymer supports with different physical properties and morphological characteristics were obtained. The polymer supports were chemically modified by sulfonation. The resultant sulfonic resins had their catalyst activity evaluated in the esterification of acetic acid with n-butanol.     

The Role of inclusion size in toughening of epoxy resins by spherical micelles

We report our finding of an optimal length scale for toughening of epoxies using spherical micelles formed by block copolymers. The amphiphilic diblock copolymer poly(hexylene oxide)‐poly(ethylene oxide) (PHO‐PEO) with 30 wt % PEO self‐assembled to form spherical micelles in a bisphenol A epoxy resin with a phenol novolac hardener. We systematically increased the size of the spherical micelles from 20–30 nm to 0.5–10 μm by swelling their PHO core using PHO homopolymer. Although all the blends were tougher than the unmodified epoxy, the largest enhancement of fracture resistance was measured in blends containing 0.1–1 μm spherical inclusions. This enhanced toughness was correlated with plastic deformation by shear banding in tensile test and greater roughness of the fracture surface. Smaller micelles neither induced plastic deformation nor contributed to surface roughness significantly whereas larger micelles acted as local defects resulting in early failure. These findings provide a framework in assessing the toughening effects of blended block copolymers on epoxy resins. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1125–1129, 2009     

Synthesis of novel silicone modified acrylic resins and their film properties

New silicone modified acrylic resins were synthesized and some of their film properties were investigated. At first, macromer (MC) was synthesized by the condensation reaction of the reactive polysiloxane intermediate (Z-6018) and 2-hydroxyethyl methacrylate (HEMA) in toluene as solvent at 110°C under nitrogen atmosphere. Then, MC was reacted with 2-dimethylaminoethyl methacrylate (DMAEMA) at different mole ratios (1:1, 1:3, 1:5) by using benzoyl peroxide as initiator in toluene to obtain novel silicone acrylic resins. These resins were characterized by Fourier Transform Infrared Spectrometry (FT-IR), and their thermal properties were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. The properties of the films prepared from these resins were determined. The results showed that these resins are thermally stable polymers and all films are flexible, semi-gloss and have excellent drying, adhesion properties. Copyright © 2007 John Wiley & Sons, Ltd.     

新型耐热、疏水MQ硅树脂的合成与性能研究

以正硅酸乙酯、六甲基二硅氧烷和四甲基二乙烯基二硅氧烷为原料,通过在酸性条件的水解缩合反应合成了一种新型的MQ硅树脂(1),其结构经1H NMR,FT-IR和XRD表征。用静态接触角和热重分析分别研究了1的润湿性和热稳定性。结果表明:1的接触角为139°,具有良好的疏水性能;1失重5wt%的温度为456℃,具有高的热稳定性。     

Synthesis and properties of poly(arylene ether)s bearing sulfonic acid groups on pendant phenyl rings

Two kinds of new aromatic poly(arylene ether)s containing sulfonic acid groups were synthesized. Polymer 1 composed of tetraphenylphenylene ether and perfluorobiphenylene units was sulfonated with chlorosulfonic acid. Sulfonation took place only at the para position of the pendant phenyl rings. The average degree of sulfonation per repeating unit (m) was controlled from 1 to 4. Sulfonated polymer 2 with m = 3 was soluble in methanol and dimethyl sulfoxide and swelled in water. Incorporating bis(3,5‐dimethylphenyl)sulfone moieties into the sulfonated polymer imparts less methanol affinity. Polymers 4 with 30–65 mol % tetrakis(sulfophenyl)phenylene ether units has high decomposition temperatures above 300 °C, hydrophilicity, and good hydrolytic stability. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3211–3217, 2001     

Aliphatic-aromatic poly(ether amide)s containing oxyethylene units. Synthesis and characterization

The synthesis and characterization of aromatic polyamides containing oxyethylene units is reported, and the differences observed in polycondensation yields, molecular weights, and molecular weight distributions, as a function of the method of synthesis, are discussed. Four diamines containing oxyethylene units and aromatic rings, meta and para oriented, and their corresponding hydrochlorides were prepared as condensation monomers to be combined with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). High molecular weight polyamides were obtained by interfacial and low-temperature solution methods. Values of (OVERLINE)M(/OVERLINE)_n up to 6 × 10⁴ g/mol and (OVERLINE)M(/OVERLINE)_w up to 2 × 10⁵ g/mol could be measured by gel permeation chromatography using aromatic polyamide standards, and values of (OVERLINE)M(/OVERLINE)_n up to 2 × 10⁵ g/mol and (OVERLINE)M(/OVERLINE)_w up to 5 × 10⁵ g/mol by using polystyrene standards. © 1996 John Wiley & Sons, Inc.     

Synthesis and morphological characterization of poly(ϵ-caprolactone) and poly(2-methyloxazoline) substituted phenyl rings and phenylene oligomers

Poly(ϵ-caprolactone) (PCL) and poly(2-methyloxazoline) (POx) substituted phenyl rings (macromonomers) and the corresponding substituted polyphenylene oligomers have been synthesized in various chemical structures. Macromonomers were synthesized by ring opening polymerization. Poly(phenylene) oligomers were then synthesized by cross-coupling of the macromonomers in Ni-catalyzed polycondensation reactions. The macromonomers and oligomers have been characterized by ¹H-NMR, IR, GPC, and DSC. The effect of side chain chemistry and architecture on the resulting morphology in thin films has been investigated by atomic force micro-scopy and wide angle X-ray scattering. Polyphenylene oligomers showed layered morphologies in thin films. The orientation of the layers depended on the chemistry of the side chains and the backbone architecture. Linear oligomers containing statistically distributed segments having POx or PCL side chains showed layers perpendicular to the underlying substrate. Attachment of polystyrene end block to PCL chain together with the meta-connectivity of the backbone resulted in layers parallel to the substrate. Our results also indicate that substitution of polymeric chains to phenyl rings can induce ordered structures of macromonomers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2091–2104, 2007     

Silicon-containing flame retardant epoxy resins: Synthesis, characterization and properties

Epoxy resins with different silicon contents were prepared from silicon-containing epoxides or silicon-containing prepolymers by curing with 4,4′-diaminodiphenylmethane. The reactivity of the silicon-based compounds toward amine curing agents was higher than that of the conventional epoxy resins. The T_g of the resulting thermosets was moderate and decreased when the silicon content increased. The onset decomposition temperatures decreased and the char yields increased when the silicon content increased. Epoxy resins had a high LOI value, according to the efficiency of silicon in improving flame retardance.     

Effect of ammonium groups on the properties and alkaline stability of poly(arylene ether)‐based anion exchange membranes

Five kinds of ammonium groups functionalized partially fluorinated poly(arylene ether) block copolymer membranes were prepared for investigating the structure–property relationship as anion exchange membranes (AEMs). Consequently, the pyridine (PYR)‐modified membrane showed the highest alkaline and hydrazine stability in terms of the conductivity, water uptake, and dry weight. The chloromethylated precursor block copolymers were reacted with amines, such as trimethylamine, N‐butyldimethylamine, 1‐methylimidazole, 1,2‐dimethylimidazole, and PYR to provide the target quaternized poly(arylene ether)s. The structures of the polymers, as well as model compounds and oligomers were well characterized by ¹H NMR spectra. The obtained AEMs were subjected to water uptake and hydroxide ion conductivity measurements and stabilities in aqueous alkaline and hydrazine media. The pyridinium‐functionalized quaternized polymers membrane showed the highest alkaline and hydrazine stability with minor losses in the conductivity, water uptake, and dry weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 383–389     

Preparation of macroreticular redox resins with hydroquinone and catechol units as pendant groups and their properties

Macroreticular redox resins with hydroquinone and catechol units as pendant groups were prepared by the Friedel-Crafts reaction of macroreticular styrene/divinylbenzene copolymer with 2,5- and 3,4-dimethoxybenzyl chlorides, followed by removal of the methyl groups with hydrobromic acid. The redox capacity of the macroreticular resins was determined by oxidation of hydrazobenzene with resins in oxidized form. Resins with 1,4-benzoquinone units were capable of oxidizing hydrazobenzene, whereas those with 1,2-benzoquinone (catechol quinone) units exhibited no apparent oxidative ability; this seems to be due to a complex formation between azobenzene and the catechol units in the reduced resins. Adsorption of metallic ions onto catechol-containing resins showed a high selectivity for Hg²⁺ ion. The effects of pH, reaction time, and ion concentration on the adsorption were also studied.     

Synthesis of oligomeric epoxycyclotriphosphazenes and their properties as reactive flame-retardants for epoxy resins

Hydroxyaryloxycyclophosphazenes containing 2–4 OH groups have been synthesized by the substitution of chlorine atoms of hexachlorocyclotriphosphazene via the reaction with sodium phenolates of halogenophenols followed by the interaction with sodium monophenolate of diphenylolpropane. Oligoepoxyphosphazenes (OEPs) with molecular masses up to 2000 and the contents of epoxy groups, phosphorus, and halogens atoms about 5–8, 5–8, and 5–11%, respectively, have been obtained via the interaction of the aforementioned phosphazenes with epichlorohydrin. The curing of the OEPs with amines or acid anhydrides gives rise to the formation of self-extinguishing composites. The incorporation of the OEPs (5–75 wt %) into commercial epoxy resins followed by their curing, results in the formation of composites with excellent nonflammability or capability of self-quenching, and good dielectric, heat resistant and mechanical properties. It has been established that mixtures of common epoxides with different amounts of the OEPs can be synthesized by a “single-reactor” method.     

Synthesis, characterization, and cure properties of phosphorus-containing epoxy resins for flame retardance

An organophosphorus compound, 10-(2,5-dihydroxyl phenyl)-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DHPDOPO), was synthesized through the reaction of 9,10-dihydro-9-oxa-10-phosphaphnanthrene-10-oxide (DOPO) and p-benzoquinone, and characterized by elemental analysis, Fourier transform infrared spectrum (FTIR), and ¹H-NMR and ³¹P-NMR spectroscopes. Consequently, the phosphorus-containing epoxy resins with phosphorus content of 1 and 2 wt.% were prepared via the reaction of diglycidyl ether of bisphenol-A with DHPDOPO and bisphenol-A, and confirmed with FTIR and gel permeation chromatography (GPC). Phenolic melamine, novolak, and dicyanodiamide (DICY) were used as curing agents to prepare the thermosetted resins with the control and the phosphorus-containing epoxy resins. Thermal properties and thermal degradation behaviors of these the thermosetted resins were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Phenolic melamine-cured resins exhibited higher glass transition temperatures than the other cured resins due to the high rigidity of their molecular chain. TGA studies demonstrated that the decomposition temperatures of the novolak-cured resins were higher than those of the others. A synergistic effect from the combination of the phosphorus-containing epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermosetted resins.     

Synthesis and characterization of postsulfonated poly(arylene ether sulfone) diblock copolymers for proton exchange membranes

Sulfonated poly(arylene ether sulfone) diblock copolymers were studied through the postsulfonation process. Two kinds of hydrophobic oligomers with a molecular weight of 20 kDa were prepared in advance as block sequences and then coupled together to obtain diblock copolymers. One oligomer was synthesized from bis(4‐hydroxyphenyl) sulfone (BHPS) and 4,4′‐difluorodiphenyl sulfone (DFDPS), which was thought to be incapable of postsulfonation. The other oligomer was synthesized from hydroquinone (HQ) and 4,4′‐dichlorodiphenyl sulfone (DCDPS), which successfully proceeded to a hydrophilic sequence as a result of sulfonation onto the HQ moiety after the coupling reaction. Consequently, a diblock copolymer with high molecular weight was obtained; although its intrinsic viscosity was too low to form a tough membrane because of its high rigidity and high crystallinity. Therefore, the use of decafluorobiphenyl (10F) as a termination reagent was investigated with the aim of achieving higher coupling reactivity and a kinky property. As a result, a sulfonated diblock copolymer was successfully obtained with sufficient molecular weight and intrinsic viscosity to form the membrane, as well as with adequate thermal properties. It was observed that proton conductivity, water uptake, and the water diffusion coefficient increased with higher ion exchange capacity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 700–712, 2009     

Preparation, thermal properties and flame retardancy of phosphorus- and silicon-containing epoxy resins

Phosphorus- and silicon-containing epoxy resins were prepared from (2,5-dihydroxyphenyl)diphenyl phosphine oxide (Gly-HPO), diglycidyloxy methylphenyl silane (DGMPS) and 1,4-bis(glycidyloxydimethyl silyl)-benzene (BGDMSB) as epoxy monomers and diaminodiphenylmethane (DDM), bis(3-aminophenyl)methyl phosphine oxide (BAMPO) and bis(4-aminophenoxy)dimethyl silane (APDS) as curing agents. Epoxy resins with different phosphorus and silicon content were obtained. Their thermal, dynamic mechanical and flame retardant properties were evaluated. The high LOI values confirmed that epoxy resins containing hetero-atoms are effective flame retardants, but a synergistic efficiency of phosphorus and silicon on flame retardation was not observed.     

Synthesis and properties of biobased epoxy resins. part 1. Glycidylation of flavonoids by epichlorohydrin

Biobased epoxy resins were synthesized from a catechin molecule, one of the repetitive units in natural flavonoid biopolymers also named condensed tannins. The reactivity of catechin toward epichlorohydrin to form glycidyl ether derivatives was studied using two model compounds, resorcinol and 4‐methylcatechol, which represent the A and B rings of catechin, respectively. These model molecules clearly showed differences in reactivity upon glycidylation, explaining the results found with catechin monomer. The reaction products were characterized by both FTIR and NMR spectroscopy and chemical assay. The glycidyl ether of catechin (GEC) was successfully cured in various epoxy resin formulations. The GECs thermal properties showed that these new synthesized epoxy resins displayed interesting properties compared to the commercial diglycidyl ether of bisphenol A (DGEBA). For instance, when incorporated up to 50% into the DGEBA resin, GEC did not modify the glass‐transition temperature. Epoxy resins formulated with GEC had slightly lower storage moduli but induced a decrease of the swelling percentage, suggesting that GEC‐enhanced crosslinking in the epoxy resin networks. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and thermal properties of epoxy resins from ester-carboxylic acid derivative of alcoholysis lignin

Alcoholysis lignin (AL) was dissolved in ethylene glycol and the obtained mixture was reacted with succinic anhydride to form a mixture of ester-carboxylic acid derivatives (AL-polyacid, ALPA). Ethylene glycol-polyacid (EGPA) was also prepared from ethylene glycol. The obtained mixture of ester carboxylic acid derivatives was treated with ethylene glycol diglycidyl ether in the presence of catalytic amount of dimethylbenzylamine to form ester-epoxy resins. The curing reaction was analyzed by Ozawa's method using differential scanning calorimetry. The activation energy of curing reaction in the initial step was found to be ca. 84 kJ mol⁻¹. The molar ratios of epoxy groups to carboxylic acid groups ([EPOXY]/[AA] ratios) were varied from 0.8 to 1.3. The contents of ALPA in the mixture of ALPA and EGPA were also varied from 0 to 100%. Thermal properties of epoxy resins were studied by DSC and thermogravimetry. Glass transition temperatures of epoxy resins showed a maximum value of −11.5 °C when [EPOXY]/[AA] ratio was 1.1. T_g increased with increasing ALPA contents suggesting that lignin acts as a hard segment in epoxy resin networks. Thermal degradation temperatures of epoxy resins slightly decreased with increasing ALPA contents.     

Synthesis,cure, and composite properties of mixed allyl/propargyl cyclopentadiene resins

A series of thermosetting resins were synthesized via phase transfer reaction of allyl chloride and propargyl bromide with cyclopentadiene in the presence of a strong base. Feed ratios of 1 : 1, 3 : 1, and 5 : 1 allyl chloride to propargyl bromide were used to give resins with varying amounts of propargyl and allyl functionality. In all cases the resins could be thermally cured, without added catalyst, at temperatures below 275°C to give black, glassy, brittle materials with densities of 1.15. TGA evaluation of the resins, with heating to 1000°C, resulted in carbon yields ranging from 48 to 66% with increasing propargyl functionality causing increased values. Physical mixtures of ACP and PCP resins were also made and evaluated. Cure of the mixed materials also occurred below 275°C, and carbon yields were comparable to the corresponding APCP resin. APCP/carbon fiber composites gave good mechanical properties with flexural modulus values of 115–130 GPa and flexural strength values of 1000 MPa. Carbonization of 1 : 1 APCP/carbon fiber composites provided materials with interlaminar strength values of approximately 1.14 MPa. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2869–2876, 1998     

New polyamidation through the activation of amino groups with phenyl dichlorophosphite in pyridine

Polyamidation with phenyl dichlorophosphite (PDCP) as a new condensing agent was studied. A model reaction of benzoic acid and aniline with PDCP through a change in their addition order revealed that PDCP reacted with aniline more favorably than it did with the acid, and it could activate about 2 mol of aniline to produce benzanilide in a nearly quantitative yield. A preferential reaction with aniline occurred even in the presence of the acid. The reaction was applied to the polyamidation of dicarboxylic acids and diamines or of p‐aminobenzoic acid (PABA) with 0.6 equiv of PDCP with respect to the amino groups in pyridine/N‐methyl‐2‐pyrrolidone in the presence of LiCl. Polyterephthalamides and polyisophthalamides with moderate inherent viscosity values were produced. The polycondensation of PABA was significantly promoted by the slow addition of PDCP over a period of 20–40 min and the presence of LiCl, producing poly(p‐benzamide) with inherent viscosity values of about 2.4. Unsubstituted PDCP and PDCPs with an electron‐donating methoxy substituent afforded better results. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4126–4131, 2004