scholarly journals Microphase Separation in Oil-Water Mixtures Containing Hydrophilic and Hydrophobic Ions

2017 ◽  
Vol 119 (21) ◽  
Author(s):  
Nikos Tasios ◽  
Sela Samin ◽  
René van Roij ◽  
Marjolein Dijkstra
Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1629
Author(s):  
Xuecheng Yu ◽  
Ying Xiong ◽  
Zhen Li ◽  
Hongding Tang

Three series of silicone modified polyurethane acrylate (SPUA) prepolymers were prepared from dicyclohexylmethane-4, 4′-diisocyanate (HMDI), PPG1000, triethylene glycol (TEG), 2-hydroxyethyl acrylate (HEA), and multi-hydroxyalkyl silicone (MI-III) with tris(trimethylsiloxy)silyl propyl side groups. Their structures were confirmed by 1H NMR, 13C NMR, and Fourier transformed infrared (FTIR) analysis, and SPUA films were obtained by UV curing. The properties of films were investigated by attenuated total reflection (ATR)-FTIR, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), water contact angle (WCA), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), water and hexane resistance, and tensile testing. The results showed that the structures and dosages of MI-III could influence the polymerization properties, surface properties, water and n-hexane resistance, and thermal and tensile properties of SPUA. For instance, the surface aggregation of tris(trimethylsiloxy)silyl propyl groups (even ~2.5 wt%) could endow SPUA films with less microphase separation, good hydrophobicity, lipophilicity, thermal stability, and mechanical properties. Interestingly, obvious regular winkles appeared on the surfaces of SPUAIII films, which are characterized by relatively high WCA values. However, relatively smooth were observed on the surfaces of SPUAIII films, which also exhibit lower water absorption ratio values. Furthermore, the ordinary cotton textiles would be transformed into hydrophobic and oleophilic textiles after treating with SPUA simply, and they were used in the oil/water separation study. Among them, consistent with water and hexane resistance analysis of SPUA films, SPUAII treated cotton textiles are characterized by relatively small liquid absorption capacity (LAC) values. Thus, phenyl groups and side-chain tris(trimethylsiloxy)silyl propyl groups are helpful to improve the hydrophobicity and lipophilicity of SPUA films. SPUAII-5 (even with 5 wt% MII) treated cotton textiles could efficiently separate the oil/water mixture, such as n-hexane, cyclohexane, or methylbenzene with water. Thus, this material has great potential in the application of hydrophobic treatment, oil/water separation, and industrial sewage emissions, among others.


Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.


2001 ◽  
Author(s):  
Catherine Gautier
Keyword(s):  

2020 ◽  
Author(s):  
Bingqing qian ◽  
Haiqiao Wang ◽  
Dong Wang ◽  
Hao-Bin Zhang ◽  
Jessica Wu ◽  
...  

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 145-153 ◽  
Author(s):  
Chengua Yu ◽  
Feng Wang ◽  
Shiyu Fu ◽  
Lucian Lucia

A very low-density oil-absorbing hydrophobic material was fabricated from cellulose nanofiber aerogels–coated silane substances. Nanocellulose aerogels (NCA) superabsorbents were prepared by freeze drying cellulose nanofibril dispersions at 0.2%, 0.5%, 0.8%, 1.0%, and 1.5% w/w. The NCA were hydrophobically modified with methyltrimethoxysilane. The surface morphology and wettability were characterized by scanning electron microscopy and static contact angle. The aerogels displayed an ultralow density (2.0–16.7 mg·cm-3), high porosity (99.9%–98.9%), and superhydrophobicity as evidenced by the contact angle of ~150° that enabled the aerogels to effectively absorb oil from an oil/water mixture. The absorption capacities of hydrophobic nanocellulose aerogels for waste engine oil and olive oil could be up to 140 g·g-1 and 179.1 g·g-1, respectively.


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