Pervaporation Recovery of n-butanol from Its Dilute Solution with Natural Rubber/Styrene-butadiene-styrene Blend Membrane

Natural rubber/styrene-butadiene-styrene(NR/SBS)membrane was prepared by solution blend,and then used for recovery of butanol from its dilute solution by pervaporation(PV).The thermodynamic and mechanical properties of NR/SBS blend membrane were characterized by TGA and tensile test,respectively.A layer of relatively dense blend membrane with the thickness of about 37μm was closely cast on a layer of porous polyvinylidene difluoride(PVDF)support.And there was no obvious phase separation observed between the interface of two layers.Both flux and separation factor increased with increasing feed temperature.Butanol flux increased as feed concentration increased consistently.The blend membrane which got the best performance obtained membrane separation factor of 28.8 with total flux of 2695.2 g/m^(2)h at 70℃ when feed concentration was 4.00wt%.

Fabrication and Characterization of Poly(Styrene-Butadiene-Styrene)/Thermoplastic Polyurethane Blends

This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works were conducted on the relationships between rheological, optical properties, morphology, mechanical properties, abrasion resistance and thermostability given. The results showed that the shear viscosity of SBS not obvious effect with TPU content. The optical properties of the SBS/TPU blend that its uniform transparency. The morphology characteristics indicating the phase diversion and the variation in the size of the SBS domains from large to small as the TPU contents increased, with heterogeneous domain dispersions. Additionally, the mechanical properties, abrasion resistance and thermal resistance are improved as the amount of added TPU is increased, suggesting that the blending of SBS with TPU is consistent with the compound rule.

Thermal Stability Improvement and Structural Change of Oil Gels Formed by Styrene-Butadiene-Styrene Triblock Copolymer Induced by Adding Poly(phenylene ether)

The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg). In naphthenic oil which is a good solvent for the butadiene blocks, but a non-solvent for the styrene blocks and PPE, PPE was selectively included into styrene blocks in SBS, and induced the increase of the Tg of these blocks. The melting temperature determined by viscoelastic measurements and softening temperature of the gels were elevated by adding PPE, while no significant change was detected by adding polystyrene. The gel became opaque by adding PPE, and partially separated phases were observed by field emission scanning electron microscopy (FE-SEM). The dependence of the viscoelastic behavior on the PPE concentration can be explained by the structural change observed by FE-SEM.

Laboratory Study on CR/SBS Modified Asphalt:Preparation and Performance Characterization

Crumble rubber(CR)can be used to prepare CR and styrene-butadiene-styrene(SBS)composite modified asphalt with a good high-and low-temperature performance,meanwhile the addition of CR could work as the substitute for SBS and help reduce the content of SBS.This study contains three main parts:effect of preparation and effect of material composition as well as rheological performance characterization.Factors during the preparation,including shearing temperature,shearing time,mixing time and swelling time,were selected,while base binder,CR content,CR particle size and SBS content in material composition were considered.The effects of these factors were assessed in terms of the conventional performance(penetration,softening point,ductility and storage stability).After identifying these effects,the sample of CR and SBS modified asphalt at the selected preparing condition and material composition(CR/SBSMA)was made,and the corresponding SBS modified and CR modified asphalt(SBSMA and CRMA)were produced for the comparing reason.Subsequently,temperature sweeps from 0℃ to 80℃ were utilized to depict the viscoelasticity of these modified asphalt binders by complex modulus and phase angle.Multiple stress creep recovery tests(MSCR)at 64℃ and bending beam rheometer tests(BBR)at various low temperatures were employed to evaluate the high-and low-temperature performance,respectively.Results highlight that that CR/SBSMA could exhibit an excellent high-temperature performance(better than SBSMA),and a good low-temperature performance(reaching the level of base binder).

1-D polymer ternary composites:Understanding materials interaction, percolation behaviors and mechanism toward ultra-high stretchable and super-sensitive strain sensors

A series of 1-D polymer ternary composites based on poly(styrene-butadiene-styrene)(SBS)/carbon nanotubes(CNTs)/few-layer graphene(FLG) conductive fibers(SCGFs)were prepared via wet-spinning. Employed as ultra-high stretchable and super-sensitive strain sensors, the ternary composite fiber materials’ interaction, percolation behaviors and mechanism were systematically explored. The resultant SCGFs-based strain sensors simultaneously exhibited high sensitivity, superior stretchability(with a gauge factor of 5,467 under 600% deformation) and excellent durability under different test conditions due to excellent flexibility of SBS, the synergistic effect of hybrid conductive nanofibers and the strong π-π interaction. Besides, the conductive networks in SBS matrix were greatly affected by the mass ratio of CNTs and FLG, and thus the piezoresistive performances of the strain sensors could be controlled by changing the content of hybrid conductive fillers. Especially, the SCGFs with 0.30 wt.%CNTs(equal to their percolation threshold 0.30 wt.%) and 2.7 wt.% FLG demonstrated the highest sensitivity owing to the bridge effect of FLG between adjacent CNTs. Whereas, the SCGFs with 1.0 wt.% CNTs(higher than their percolation threshold) and 2.0 wt.% FLG showed the maximum strain detection range(600%) due to the welding connection caused by FLG between the contiguous CNTs. To evaluate the fabricated sensors, the tensile and the cyclic mechanical recovery properties of SCGFs were tested and analyzed. Additionally, a theoretical piezoresistive mechanism of the ternary composite fiber was investigated by the evolution of conductive networks according to tunneling theory.