Synthesis And Property Of Benzoxazine Resins Containing Ionic Groups

Benzoxazine resins are a new class of high-performance thermosetting resins.It has excellent heat-resistance,mechanical property,flame retardancy,dimensional stability and high molecular design flexibility.It has been used in aerospace,transportation,electronics manufacturing,and other fields.However,most of the currently developed benzoxazine resins are hydrophobic,which limits their application in hydrophilic environments,such as surfactants,polyelectrolyte membranes.Therefore,the development of hydrophilic and even water-soluble benzoxazine resins is very meaningful to extend its application field.In this dissertation,we aim to develop functional benzoxazine resins containing ionic groups.By introducing ionic groups at the molecular level,two kinds of anionic benzoxazine surfactants and three kinds of cross-linked polybenzoxazine films containing sulfonic acid group,quaternary ammonium group,and zwitterionic group were synthesized,respectively.Synthesis and properties of these benzoxazine resins were systematically studied.The main contents and results of this dissertation are shown as follows:Part ?:carboxyl group-containing benzoxazine surfactant based on biomassA novel bio-based benzoxazine surfactant(Ca-g)was synthesized via a Mannich reaction using renewable glycine and cardanol as raw materials.Styrene containing emulsions and polystyrene(PS)latex were prepared based on Ca-g surfactant.In addition,the in vitro cytotoxicity of Ca-g and its triglceride emulsion were also investigated.These results showed that Ca-g surfactant exhibited high efficiency for stabilizing styrene emulsions.An addition of only 1.7 w/v%stabilized the high internal phase emulsion(HIPE)with styrene volume fraction up to 90%.More interestingly,HIPE exhibited a pH-sensitive property and was easily formed at pH values from 9.0 to 12.0.Furthermore,polystyrene latex particles were obtained via HIPE polymerization.Ca-g showed lower cytotoxicity against the Hela cell line.A stable triglceride-in-water emulsion stabilized by Ca-g was prepared.The bio-based Ca-g surfactant may have potential use in cosmetics and daily cleaning products.Part ?:sulfonic acid group-containing benzoxazine surfactant and its waterborne benzoxaizne resinsA sulfonic acid group-containing benzoxazine surfactant(SBZ)was synthesized via a Mannich reaction using sodium 4-hydroxybenzenesulfonate and n-dodecylamine as raw materials.SBZ surfactant was used to emulsify the hydrophobic benzoxazine resin(BZ).A series of waterborne benzoxazine resin(WBR)emulsions were prepared.The effects of SBZ concentration and oil-water ratio on the behavior of WBR emulsions were studied.Furthermore,polybenzoxazine film was prepared by curing a WBR emulsion with 50 vol%BZ.The results showed that SBZ had a strong emulsifying capacity.The lower concentration of SBZ(2 w/v%)stabilized high solid content(50-80 vol%)and stable WBR emulsions.After curing the WBR emulsion,a transparent and flexible polybenzoxazine film was fabricated.The SBZ surfactants were incorporated into the benzoxazine resin matrix after ring-opening polymerization.The tensile strength and elongation at break of the film were 7.4 MPa and 9.2%,respectively.The film exhibited excellent heat resistance with a glass transition temperature of 288?.This work provides a new strategy for the development of high heat-resistant and environmentally friendly waterborne benzoxazine coatings.Part ?:sulfonic acid group-containing benzoxazine resin for proton exchange membraneA benzoxazine oligomer(PBZ)was synthesized through Mannich reaction and ring-opening polymerization using p-cresol,aniline and paraformaldehyde as raw materials.Subsequently,sulfonic acid group-containing benzoxazine oligomer(H-SPBZ)was obtained through sulfonation of PBZ and followed by ion exchange reaction.Finally,cross-linked polybenzoxazine membranes(SPM)containing sulfonic acid group were fabricated by copolymerizing H-SPBZ with bisbenzoxazine monomer.Properties of SPM membranes including conductivity,methanol permeability,oxidative stability,dimensional stability,heat resistance,and mechanical property were studied in detail.The results showed that the linear type molecular design of benzoxazine oligomer improved the film-forming property.A membrane with a size of 8 cm × 7 cm × 170 ?m was fabricated.SPM-15 membrane had good mechanical property.Its tensile strength and elongation at break were 9.6 MPa and 8.5%,respectively.Its conductivity was 25 mS/cm at 80? and 100%relative humidity.Its methanol permeability was 0.49 × 10-6 cm2/s,which was about one fifth of the value of Nafion-117 membrane(2.37 × 10-6 cm2/s).The membrane exhibited good oxidation stability.After treatment in Fenton's reagent(3 wt%H2O2+3 ppm FeSO4)at 80?,the weight loss percent of SPM-15 membrane was 1.3%,which was comparable to that of Nafion-117 membrane(1.5%).The SPM-15 membrane also presented better dimensional stability.The water uptake and swelling ratio at 80? were 12.8%and 2.8%,respectively.In addition,SPM-15 membrane had good heat resistance.This work provides a new idea for the development of high heat-resistant and alcohol resistant proton exchange membrane.Part ?:quaternary ammonium group-containing benzoxazine resin for anion exchange membraneNovel quaternary ammonium group-containing main-chain benzoxazine oligomers(QBZs)were synthesized via Mannich reaction,quaternization,and ion exchange reaction using bisphenol A,4,4'-diaminodiphenyl methane,hordenine,and paraformaldehyde as raw materials.Furthermore,the cross-linked polybenzoxazine(PQBZ)membranes containing quaternary ammonium were fabricated using solution casting and programmed temperature curing methods.Properties of PQBZ membranes including conductivity,methanol permeability,dimensional stability,alkaline stability,oxidative stability,heat resistance,and mechanical property were systematically studied.The results showed that the main-chain type molecular design of QBZ improved the film-forming property.A large membrane with a size of 10 cm × 8 cm ×100 ?m was prepared.The tensile strength and the elongation at break of PQBZ membrane were 11.9 MPa and 12.8%,respectively.The PQBZ840 membrane exhibited a higher hydroxide conductivity of 58.5 mS/cm at 80? and 100%relative humidity.It showed a very low methanol permeability of 2.7 × 10-8 cm2/s,which was near two orders of magnitude lower than that of Nafion-117 membrane(2.37 × 10-6 cm2/s).The membrane had good alkaline stability and oxidation stability.After 400 hours of treatment in 1.0 M KOH at 60?,75.4%of hydroxide conductivity was retained.After 72 hours of treatment in Fenton's reagent(30%H2O2+30 ppm FeSO4)at 68 ?,the weight loss percent of PQBZ840 membrane was 17.6%,which was much less than that of AMI-7001 anion exchange membrane(42%).Compared with other reported anion exchange membranes,the PQBZ840 membrane also presented better dimensional stability,higher heat resistance,and mechanical property.Overall,this novel polybenzoxazine membrane shows great potential for anion exchange membrane in alkaline methanol fuel cell.Part V:zwitterionic group-containing benzoxazine resin for antifouling coatingSulfobetaine group-containing benzoxazine monomer and main-chain benzoxazine oligomer were synthesized via Mannich reaction and quaternization using hordenine,bisphenol A,4,4'-diaminodiphenyl methane,and paraformaldehyde as raw materials.Furthermore,the cross-linked polybenzoxazine membranes containing sulfobetaine group were fabricated using solution casting and programmed temperature curing methods.Properties of the cross-linked polybenzoxazine membranes including surface hydrophilicity,antifouling property,mechanical property,and thermal stability were studied in detail.The results showed that the reaction of the tertiary amine group in the side chain of benzoxazine monomer(or main-chain benzoxazine oligomer)with 1,3-propane sultone can easily and efficiently introduce zwitterionic group(sulfobetaine)into benzoxazine resin.The sulfobetaine group-containing PSHM membrane exhibited good hydrophilicity with a static contact angle of 74.8°.The PSHM functionalized surface showed excellent antifouling property,which reduced protein adsorption by 98%compared to the bare surface.It presented good mechanical properties.The adhesion strength and pencil hardness were grade 1 and 6 H,respectively.In addition,it had good heat-resistant property.Its glass transition temperature and the temperature of 5%weight loss were 218? and 269?,respectively.This work provides a simple and efficient method for preparing cross-linked polysulfobetaines.The PSHM prepared by this method has potential application in the field of high heat-resistant antifouling coatings.