Effects of coagulation-bath conditions on polyphenylsulfone ultrafiltration membranes

Polyphenylsulfone(PPSU)ultrafiltration membrane with different structures was prepared by non-solvent-induced phase separation.The effects of coagulation bath conditions(concentration and temper-ature)on membrane morphology,pure water flux,pore size,porosity,and contact angle were studied and discussed based on ternary-phase diagrams.Results indicated that water had stronger coagulant power than ethanol,and that the morphology of the membrane prepared from the polyphenylsulfone/1-methyl-2-pyrrolidinone/H2O(PPSU/NMP/H2O)system had finger-like structures.Conversely,sponge-like struc-tures were observed for the PPSU/NMP/(NMP-H2O)and PPSU/NMP/(70NMP-EtOH-H2O)systems.Ethanol also greatly influenced on membrane structures.According to the Scanning electronic micro-scopy(SEM)image,the composition(mass fraction)of casting solution is 16％PPSU-84％NMP and the coagulation bath consisting of 70％NMP-26％H2O-4％C2H5OH.Meanwhile,the PPSU ultrafiltration mem-brane with spong-like was prepared under 8℃coagulation bath.The formation of sponge-like structure reduces the pure water flux of ppsu membrane from 488.39 L·m-2·h-1 to 36.04 L m-2·h-1.It also reduces the gas permeability,porosity,and pore size of the membrane.The addition of ethanol and NMP into the coagulation bath increases the roughness of the PPSU ultrafiltration membrane and reduces the hydrophilicity of the membrane.     

光催化膜对水中腐植酸的去除及积垢机理

利用湿式相转化方法制备TiO₂/聚苯砜（polyphenylsulfone,PPSU）/聚醚亚硫胺（polyetherimide,PEI）催化膜应用于水中腐植酸（humic acid,HAs）的去除及积垢机理研究。结果表明,随着亲水性PEI比例增加,光催化膜的纯水通量和HAs的过滤通量越大,去除效率越低;且随着光照时间的延长去除效率越趋于稳定,且有回复的现象。在0.2MPa操作压力下,制备的TiO₂/PPSU/PEI （1%/50%/50%）膜具有最佳的可逆阻抗力比例（R_c/R_t=48.24%）;其渗透通量、HAs去除效率及反洗后通量分别为34.0L/（m²·h）、63.2%及22.5L/（m²·h）,具有较佳的通量及HAs去除效率。     

Polyphenylsulfone (PPSU) for baby bottles: a comprehensive assessment on polymer-related non-intentionally added substances (NIAS)

Polyphenylsulfone (PPSU) is a new material for the production of baby bottles. PPSU is a polyether plastic formally composed of bisphenol S (BPS) and 4,4?-dihydroxybiphenyl (DHBP), which both have slight endocrine activities in in vitro tests. So far, little is known about the presence and the release of potentially hazardous substances from PPSU baby bottles. In this study, we present a three-step approach for the analysis of PPSU starting with polymer characterisation in terms of chemical structure, total oligomer content and hydrolytic stability. Second is the determination of extractables focussing on monomers, monomer derivatives, linear and cyclic oligomers below 1000 Da and residual solvent. Third is a risk assessment on migration-related substances in accordance to European Union plastics regulation no. 10/2011 based on triplicate consecutive migration experiments using official milk simulant 50% ethanol. We analysed five types of PPSU baby bottles from different brands as well as corresponding raw materials from different manufacturers by various analytical techniques (high-performance liquid chromatography (HPLC)-diode array detector /fluorescence detector/Corona/electrospray ionisation-MS, HPLC-size exclusion chromatography, gas chromatography-mass spectrometry (GC-MS), ¹H-NMR). We found significant variations of PPSU materials from different producers with regard to polymer and oligomer chain end groups (methoxylation, chlorination), while total oligomer content below 1000 Da was similar (mean about 0.48%). BPS was not detected above 0.3 mg/kg polymer in any PPSU sample. Residual DHBP content ranged between 1.7 and 15.5 mg/kg polymer. The most common oligomer in all PPSU samples was the cyclic tetramer (about 1200 mg/kg polymer), which is the only cyclic compound below 1000 Da. Residual solvent, sulfolane, was determined to a maximum of 1300 mg/kg polymer. In migration tests, we detected exceedances of neither specific migration limits for listed substances nor of thresholds of toxicological concern for non-listed substances (monomer derivatives, oligomers). Based on our analytical results, no concerns exist regarding migration of polymer-related substances from PPSU baby bottles.