Aminated Poly Vinyl Chloride Research Articles

Preparation of the interfacial enhanced PA/APVC nanofiltration membrane based on the in-situ amination of substrate membrane

In this research, a novel interfacial enhanced thin film composite nanofiltration (TFC NF) membrane with nail-fixed like surface structure and wave line like cross-section structure, good permeability and superior interfacial stability was prepared by interfacial polymerization (IP) on one-step in-situ aminated polyvinyl chloride (APVC) support layer. The effects of amination agent (triethylenetetramine, TETA) content on the support layers and the effects of the support layers with different degrees of amination on the performance of the TFC NF membranes were studied comprehensively. Furthermore, the interfacial bonding strength of the TFC NF membrane was explored by the inverse permeation test. It was concluded from the results that higher TETA content in casting solution led to the APVC membrane to form macroporous surface structure, thinner top skin layer and larger mean pore size. Meanwhile, more TETA molecules were grafted onto the PVC chains through nucleophilic substitution to participate in IP in a synergistic manner. Accordingly, the corresponding TFC NF membrane formed a nail-fixed like surface structure similar to semi-free-standing polyamide (PA) layer and wave line like cross-section structure with thinner and denser active layer. The water flux of the TFC NF membrane prepared with the optimized APVC membrane as the substrate membrane was increased by 395% at 0.6 MPa compared with the TFC NF membrane prepared with PVC membrane as the substrate membrane, while Na2SO4 rejection did not sacrifice and increased by 3.48%, which manifested that unique structure was favorable to speed up the water transmission and effectively conquered the trade-off effect. Moreover, the representative TFC NF membrane prepared with optimized APVC membrane as the substrate membrane with strong covalent bond between support layer and active layer demonstrated superior interfacial stability in the short-term circulating inverse permeation test.

Design of a novel interfacial enhanced GO-PA/APVC nanofiltration membrane with stripe-like structure

New-style thin film composite nanofiltration (TFC NF) membrane with a stripe-like surface structure, superior interfacial bonding, expected permeability and antifouling performance was successfully fabricated via interfacial polymerization. The aminated polyvinyl chloride (APVC) membrane prepared by amination reaction of polyvinyl chloride (PVC) with triethylenetetramine (TETA) was used as the support layer. The new graphene oxide-polyamide (GO-PA) selective layer was formed by adding graphene oxide (GO) to the aqueous solution to participate in the interfacial polymerization process. The effects of amination modification of PVC substrate membrane and addition of GO during the interfacial polymerization on the structure and performances of the TFC NF membranes were studied. The results indicated that both of the amine group on the surface of the APVC membrane and GO participated in the interfacial polymerization, which endowed the GO-PA/APVC membrane with a new-style stripe-like surface structure and a thicker, gradually looser cross-sectional structure. Meanwhile, the effective desalination active layer of the GO-PA/APVC membrane was much thinner than that of the PA/APVC membrane. The special structure was beneficial to accelerate the speed of water transmission and effectively overcome the trade-off effect during the desalination process. Therefore, the water permeability of GO-PA/APVC membrane was improved more than 60% while the salt rejection remained stable compared with PA/APVC membrane. Moreover, the GO-PA/APVC membrane exhibited superior interfacial bonding and antifouling properties.

Preparation and performance of poly (vinyl chloride)/aminated poly (vinyl chloride) blend ultrafiltration membranes

AbstractPolyvinyl chloride (PVC) was treated with aqueous solution of ethylenediamine to obtain aminated polyvinyl chloride (APVC). PVC/APVC blends ultrafiltration membranes, by phase inversion technique. Different polymer blend compositions with and without an additive, like Poly (ethylene glycol) of molecular weight 600 Da were also prepared. The blend membranes were characterized and evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), water contact angle, water content, pure water flux, and membrane porosity to investigate the influence of APVC on the final properties of the membranes. The presence of amine functional group was confirmed by FTIR spectrum. SEM analysis showed that the blend PVC membranes have thinner top layer and higher porosity in the sublayer. The blend membranes showed an increase in overall porosity, hydrophilicity, and water content, with increase in APVC content and in the presence of additive. The fouling resistant capability of the m...

Covalent Immobilization of β‐Galactosidase onto Amino‐Functionalized Polyvinyl Chloride Microspheres: Enzyme Immobilization and Characterization

ABSTRACTIn this study, β‐galactosidase (Aspergillus oryzae) was covalently immobilized onto aminated polyvinyl chloride (PVC) via glutaraldehyde coupling. Effect of immobilization conditions was investigated. The maximum obtained immobilization yield is 27 units g−1 while the maximum expressed activity is 12 µmol min−1 g−1. The optimum pH of the free enzyme was observed at 5.2, whereas the optimum pH of the immobilized one was schiffed to 4.4. The optimum temperature for both the free and immobilized forms was recognized at 60°C. A change in the temperature profile of the immobilized enzyme below 60°C was observed when response to the elevation temperature was less than that to the free counterpart. The Km and Vmax values of the free and immobilized β‐galactosidase were found to be 52.03 and 123.1 mM, and 6.12 and 9.98 µ mol/min, respectively. Lactose hydrolysis, 500 mL of 100 mM concentration, was studied using 400 units of either free or immobilized enzymes at pH 6.0 and 60°C. Almost 80% hydrolysis percentage has been obtained after 6 h hydrolysis time with immobilized enzyme compared with 63% hydrolysis percentage obtained after 2 h for the free counterpart. Investigation of the operational stability at 40°C shows that the immobilized enzyme kept its activity for 5 h over 10 successive lactose hydrolysis cycles, which provides potentials for practical application in milk and whey hydrolysis. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2014, 33, 21379; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21379

Activated nitrogen-doped carbons from polyvinyl chloride for high-performance electrochemical capacitors

Activated nitrogen-doped carbons (ANCs) were prepared by carbonization/activation approach using aminated polyvinyl chloride (PVC) as precursor. ANCs exhibit larger porosities and higher specific surface areas than those of their nitrogen-free counterparts for the same KOH/carbon ratio. The specific surface area of ANC-1 is up to 1,398 m2 g−1 even at a low KOH/carbon ratio of 1:1. Fourier transform infrared spectroscopy investigation of the nitrogen-enriched resin precursor indicates the efficient dehydrochlorination of PVC by ethylenediamine at a low temperature. The nitrogen content and the population of nitrogen functionalities strongly depend on the KOH/carbon ratios and decrease drastically after KOH activation as seen from the elemental and X-ray photoelectron spectroscopy analysis. The surface concentration of N-6 and N-Q almost disappears and the dominant nitrogen groups become N-5 after KOH activation. The highest specific capacitance of ANCs is up to 345 F g−1 at a current density of 50 mA g−1 in 6 M KOH electrolyte. ANCs also exhibit a good capacitive behavior at a high scan rate of 200 mV s−1 and an excellent cyclability with a capacitance retention ratio as high as ∼93 % at a current density of 2,000 mA g−1 for 5,000 cycles.