Synthesis and Characterization of a Novel Hyperbranched Poly(aryleneimine) Polymer

(Department of Polymer and Composite Materials, School of Materials Science and Engineering, Beihang University, Beijing 100083) The new hyperbranched monomer of the group. A hyperbranched polymer having a weight-average molecular weight of 13,900 was obtained by a ring-opening reaction between the imino group and the epoxy group in the hyperbranched monomer. The product was characterized by IRH-NMR and GPC. DSC was used to explore the behavior of synthetic hyperbranched polymer cured epoxy resin.

Fund Projects: Fundamental Science Foundation for Science (98G51080) and Special Research Fund for Doctoral Programs in Colleges and Universities (98000601) Jointly funded hyperbranched polymers are polymers obtained by one-step reaction of ABn (Preparation 2) type monomers, with highly branched structures . It and dendrimers are collectively referred to as dendritic branched macromolecules, both having spherical or nearly spherical molecular shapes and numerous peripheral groups. Its unique structure and properties and its easy-to-prepare characteristics have attracted widespread attention. In the coatings field, thermosetting resin toughness, drug release agents, conductive polymers, copolymer modification and other fields have a wide range of applications in this paper through phenol, formaldehyde, aniline The Mannich reaction and epoxidation of the Mannich product resulted in a hyperbranched monomer with one epoxy group and two to three aromatic imino groups. Through the reaction of epoxy groups and imino groups, hyperbranched polymers are obtained. The rich imino groups can undergo ring-opening reactions with the epoxy groups in the epoxy resin, which can be used as a curing agent for epoxy resins. Hyperbranched monomers and their corresponding hyperbranched polymers have not been reported in 1 benzoxazine (3a, 3b) Fig.3 a, b are the infrared spectra of the Mannich product and the ether phase material after separation In Fig.3(a), the OH stretching vibration appears at 3700cm-3500cm-1. Because of the hydrogen bonding, the presence of phenolic OH out-of-plane vibration and c-OH contraction peak at the peak 1 further proves the existence of phenolic hydroxyl group. . The NH vibration peaks in secondary amines exhibit double absorption peaks at 3,405 cm 1 and 3,334 cm 1 due to hydrogen bonding. The strong absorption peaks at 1317 cm 1 and 1248 cm correspond to the secondary amine's CAr-N stretching vibration and Cr-N stretching 1 strong aromatic ring substitution type, respectively. The characteristic peaks 872cm-1 and 817cm1 have two absorption peaks, one strong and one strong, corresponding to isolated hydrogen on the substituted benzene ring in 1a1b and two adjacent hydrogens on 1b, respectively. Strong absorption peaks at 750cm-1, 690cm-1 The presence of a monosubstituted phenyl ring 3 3 (b) is the infrared spectrum of the ether phase material. The difference from Fig. 3(a) is that the OH stretching vibration peak and the C-OH stretching vibration peak all become weak, and the out-of-plane vibration of the phenolic OH at 1355 cm-1 disappears completely. The ether phase material contains only a very small amount of phenolic hydroxyl groups. Absorption peaks of secondary amines have been weakened, new absorption peaks have appeared at 1225cm-1G-N stretching vibration and 1367cm-1CAr-N stretching vibration of tertiary amines, due to secondary amine reaction during the production of benzoxazine rings. The strong characteristic absorption peak of benzoxazine appeared at the tertiary amine generated at 933 cm-1, indicating that the ether phase material contained a large amount of benzoxazine.

0.28 and 0.05 confirm the results of IR and NMR analysis. The Mannich reaction of phenols, aldehydes, and amines is usually performed under acid catalysis and the reaction is severe. If primary amines are used, the secondary Mannich reaction is prone to occur, leading to an increase in the molecular weight of the product in order to avoid the occurrence of secondary Mannich reactions. No acid is added in the reaction. The use of phenol's weak acidity catalyzes the reaction to be more stable and the aniline is excessive. In order to effectively control the molecular weight of Mannich product under different conditions measured by steam osmotic pressure method in the secondary Mannich reaction, the results are shown in Tab. 1 When the ratio of phenol, formaldehyde and aniline is 1:3.5:5, The molecular weight of the product is 377, corresponding to Ml in Tab.1, which is a mixture of la and lb. When the feed ratio is the same and a small amount of hydrochloric acid (0.2 mol/L) is added to the reaction system, the molecular weight of the product is 620, indicating that the secondary mannose has occurred. The Nich reaction corresponds to the proton peak of the benzene ring hydrogen for M2 to 7.28, the proton peak near the imino group at 6,90, and the proton peak near the phenolic hydroxyl group at 4.45 (Fig. 4(b)). The proton peak weakened, and the proton peak of the phenolic hydroxyl group almost disappeared. 5.40, 4.60 near the occurrence of the characteristic proton peaks of the two methylene groups on the oxazine ring, and the corresponding position of a in the aprotic peak appears after the heavy water exchange of the Mannich product. The benzene hydrogen content is calculated to be 72 31%, close to 1a. Heavy water exchange calculation results. This shows that the Mannich product is a predominant mixture of 1a, while the ether phase material is benzoxazine (3a, 3b). The benzoxazine does not contain phenolic hydroxyl groups and thus does not undergo epoxidation. Its presence leads to the final product. Epoxy value is low. The epoxidation reaction at 1 and 951 cm 1 of the Mannich 2.2 Mannich product corresponds to the symmetric stretching vibration and asymmetric stretching vibration of the epoxy ring. Fig. 4(c) is its 1H-NMR spectrum, and the proton peak of the methylene group on the epoxy group is 2.69, 289), indicating that the epoxidation of the epoxy group with 1a and 1b is difficult The oxidation reaction was carried out for 4 h, the product epoxy value was 0.16, the reaction time was doubled, and the epoxy value slightly increased to 0.19, which was still lower than the theoretical epoxy value (0.231) and the epoxy value was 0.1. In the primary epoxidation reaction, the epoxy value can reach 0.28, slightly higher than the theoretical epoxy value, probably because the hyperbranched reaction of part of the 2.3 epoxidation products during the secondary epoxidation process can be obtained from Tab.2. The effect of temperature, time and catalyst on the molecular weight of the hyperbranched product is seen. Under the condition of no catalyst, the number average and weight average molecular weight of the hyperbranched product are all increased with the extension of the reaction time. Increasing the reaction temperature from 120C to 150C can significantly reduce the reaction time. When BF3-ether solution is added as a catalyst, the reaction can be carried out at 120° C. and BF3 accounts for 1.5% of the hyperbranched monomer mass. In 2 hours, a product having a weight average molecular weight of 8700 is obtained, and the mass percentage of BF3 increases. When 3%, the product with a weight average molecular weight of 13,900 was obtained. Further increase of the amount of catalyst may make the molecular weight distribution of the product too wide. Finally, the amount of the catalyst was set to 3% of the mass of the hyperbranched monomer. DSC curves for 4,4'-sulfonyl diphenylamine (DDS) and hyperbranched products (HBP) curing AG-80 epoxy resin. The mass ratio of the resin to the curing agent is 100:60. As can be seen from Fig. 5, the hyperbranched product is used as a curing agent for the epoxy resin, and the initial exothermic temperature is lower than that of the DDS. This is due to overspending. The polymer surrounding is rich in imino groups, and the reaction heat is concentrated, making the curing more likely to occur. On the other hand, the peak shape of the exothermic peak of the curing reaction is more complicated and the peak top temperature is increased. This may be due to the structure of hyperbranched products. Complex and contains only aromatic secondary amines, and DDS curing agent contains aromatic primary amines. Hyperbranched polymer cured epoxy resin properties are still under study.