| الملخص | Abstract
New unsaturated maleamic acid (USMA) was synthesized by the reaction of maleic anhydride and 4-aminobenzoic acid in acetone. USMA was crosslinked with styrene in the presence of benzoyl peroxide. Subsequently the terminal carboxylic groups of USMA reacted with epoxy resin in the presence of triethyl amine, afforded styrenated poly(ester -amide) resin SPEM. The structures of the obtained products were characterized by FT-IR, 1HNMR and C.H.N elemental analysis. The new SPEM resin were reinforced with 10wt.% of fillers such as, Zeolite, Bentonite and Silica. The thermal properties of the reinforced SPEM resins were investigated by thermal gravimetric analyzer (TGA). SPEM resin (reinforced with Zeolite type A, Bentonite calcium and Silica) showed enhanced thermooxidative stability compare to fillers free SPEM resin, and TG curves showed presence of char yield of about 33% up to 700oC.
Keywords: poly(ester-amide); unsaturated amide maleamic acid; epoxy resin; TGA analysis .
Introduction
Unsaturated polyesters (UP) are characterized as a high thermally stable polymers with favorable physical and chemical properties, therefore they have a widespread field of applications such as, microelectronic, aerospace, automotive industries, building constructions and furniture. The production technique is quite well known and no sophisticated equipment or controls are needed. The unsaturated polyester, containing double bonds within the polymer chain, which is produced by step-growth polycondensation reaction on an unsaturated diacide or anhydride, such as fumaric acid or maleic anhydride, with a diol. Most crosslinking of the unsaturated polyester is
accomplished by co-polymerization with alkene monomers such as styrene or methyl methacrylate, or others using radical initiators. On the other hand, the reaction of unsaturated anhydride such as maleic anhydride with diamines leads to form bisamic acid. Unsaturated polyesters resins can be compounded with different additives and filling materials to improve and enhance the physical and mechanical properties. Another type of polymer is obtained by the interaction of a monofunctional unsaturated acid with a bisphenol diepoxide (epoxy resin) having unsaturated sites at the two ends of the chain and then it mixed with a vinyl monomer such as styrene. This resin is called vinyl ester, and its appearance, handling properties, and cure is similar to UP resins.
Experimental
Synthesis of unsaturated maleamic acid (USMA)
In a 200 mL round bottom flask charged with maleic anhydride (20.0g, 0.2 mol) and 50 mL acetone, magnetic bar stirrer, and the flask placed in an ice bath. A solution of 4- aminobenzoic acid (27.9g, 0.2 mol) in 100 mL acetone was added drop wise via dropping funnel over a period of 30 min with continuous stirring. The contents of the flask were further stirred for 3 hrs at 0-5oC and continued at room temperature for another 24 hrs.
Crosslinking of USMA with Styrene
USMA (10.0g) and 100 mL dimethyl acetamide were introduced into a 250 mL round bottom flask, equipped with a condenser, a magnetic stirrer, and the flask placed in an oil bath. The content of the flask was stirred until a clear slightly yellowish solution formed, indicating complete dissolution of the USMA. Then, 5 gm of styrene monomer (about 50% of the weight of USMA) and 0.01 gm of benzoyl peroxide were added. and the reaction temperature was gradually raised up to 80 oC with continuous stirring for 2 hrs. Upon addition of chilled distilled water (250 mL), a dark red viscous material precipitated which was collected and thoroughly washed with 200 mL of acetone. A dark red viscous product was obtained, yield 90%.
Reinforcement of Styrenated SPEM resin
Three different fillers Bentonite, Zeolite and Silica were used to reinforce the obtained products. About 10%wt. of the filler mixed with SPEM, and then dried at 100oC in an oven for 3hrs.
Conclusions
Unsaturated amide maleamic acid (USMA) was synthesized from reaction of maleic anhaydried and 4-aminobenzoic acid and then crosslinked with styrene in the presence of benzoyl peroxide. The polyester was formed by reaction the later soluble compound
with epoxy resin in the presence of triethyl amine as a catalyst. The molecular structure of the new polyester was confirmed by C.H.N elemental analysis, FTIR and 1HNMR
spectroscopy. The SPEM resin was reinforced with 10% of three types of fillers (Bentonite, Zeolite and Silica). The reinforced SPEM exhibited enhanced thermo- oxidative stability compared to the neat SPEM.
References
1- Anderson, T.F.; Messick, V.B. Developments in Reinforced Plastics-1: Resin
Matrix Aspects, Prichard, G., Ed., Applied Science Publishers: London, 1980, pp.
29–58.
2- Young, R.E. Unsaturated Polyester Technology, Bruins, P.F., Ed., Gordon and
Breach Science Publishers: New York, 1976, pp. 315–342.
3- O’Hearn, T.P., in Engineered Materials Handbook, Vol. 2, Engineering Plastics, ASM International: 1988, pp. 272–275.
1HMNR spectrum of SPEM Re | en_US |
