T functionality [1]. Polyamide-imide (PAI) is really a modified polyimide, which normally has repeated structural

T functionality [1]. Polyamide-imide (PAI) is really a modified polyimide, which normally has repeated structural units (Scheme 1). It can be seen in the molecular structure that PAI contains two structural units, amide bond and imide ring, so PAI has some performance advantages over PA and PI, which include high-temperature resistance, corrosion resistance, friction and put on resistance, fantastic mechanical properties, and can be compounded with several substances, and so forth. PAI is usually a special engineering plastic with excellent functionality, which could be applied in particularly serious working situations [5,6].Copyright: 2021 by the authors. Licensee MDPI, Basel, Switzerland. This short article is an open access short article distributed under the terms and conditions in the Inventive Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Components 2021, 14, 6376. https://doi.org/10.3390/mahttps://www.mdpi.com/journal/materialsMaterials 2021, 14,two ofScheme 1. PAI molecular structural formula.PAI polymer synthesized by 4,4′-diaminodiphenyl ether has greater complete properties, and the raw material is affordable, which has better engineering application prospects. two,2′-bis (trifluoromethyl)-4,4′-diaminophenyl ether has the exact same principal chain structure as four,4′-diaminodiphenyl ether, and the side chain includes two trifluoromethyl groups, which has high fluorine content. Research have shown that introducing fluorine or fluorine-containing groups into the molecular structure can lessen the moisture absorption rate of supplies [7], increase the heat resistance [8,10], strengthen the wear resistance [113], increase the solubility [14], and so on. There had been couple of reports onthe effects of fluorine atoms and fluorine-containing groups on PAI. In this paper, two,2′-bis (trifluoromethyl)-4,4′-diaminophenyl ether and 4,4’diaminodiphenyl ether had been compounded to synthesize PAI by the acyl chloride GS-626510 Purity & Documentation process [5,15]. The effects of trifluoromethyl on heat resistance, friction and put on resistance, hydrophobicity, and mechanical properties of PAI supplies have been studied to prepare PAI supplies with superb properties. 2. Experimental 2.1. Supplies 4,4′-diaminodiphenyl ether was analytically pure and bought from DNQX disodium salt In Vivo Aladdin (Shanghai, China). 2,2′-bis (trifluoromethyl)-4,4′-diaminophenyl ether was analytically pure and purchased from Changzhou Sunshine Pharmaceutical Technologies Co., Ltd. (Changzhou, China). 1,2,4-trimellitic anhydride acyl chloride(TMAc) was bought from Tokyo Chemical Business (Tokyo, Japan). Triethylamine as an acid-binding agent and catalyst was purchased from Aladdin (Shanghai, China). Acetic anhydride was analytically pure, employed as dehydrating agent, purchased from Aladdin (Shanghai, China). N-methylpyrrolidone(NMP) as aprotic polar solvent was bought from Aladdin (Shanghai, China). 2.two. Preparation of PAI PAI synthesized by four,4′-diaminodiphenyl ether and TMAC was named PAI(O). When the molar ratio of 4,4′-diaminodiphenyl ether to 2,2′-bis (trifluoromethyl)-4,4′-diaminophenyl ether is (9:1), (7:three), (5:5), (three:7) and (1:9), the synthesized PAI terpolymers had been named PAI-1,PAI-2,PAI-3,PAI-4,PAI-5 in turn.PAI synthesized by 2,2′-bis (trifluoromethyl)-4,4’diaminophenyl ether and TMAC was named PAI(F).The preparation method was as follows: (1) Polymerization course of action Beneath the protection of nitrogen, NMP was added into a 500 mL four-necked flask, as well as the level of NMP was eight occasions the total mass of trimellitic anhydride acyl chloride and diamine monomer.