Polymer processing
Shahab Hoseinpour; Yoones Jafarzadeh; Reza Yegani; Sepideh Masoumi
Abstract
The aim of the present work is to enhance the antifouling properties of polypropylene (PP) membrane based on hydrophilicity improvement. Different contents of neat and modified nanodiamond (0.25, 0.50, 0.75 and 1.00 wt.%) were embedded into PP membranes. Nanodiamond nanoparticles were carboxylated by ...
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The aim of the present work is to enhance the antifouling properties of polypropylene (PP) membrane based on hydrophilicity improvement. Different contents of neat and modified nanodiamond (0.25, 0.50, 0.75 and 1.00 wt.%) were embedded into PP membranes. Nanodiamond nanoparticles were carboxylated by heat treatment method and the presence of carboxyl functional groups on the surface of nanoparticles was confirmed by FTIR analysis. Membranes were then characterized by FESEM, contact angle and tensile strength tests. At the same content of nanoparticles, hydrophilicity, pure water flux and tensile strength of PP/ND-COOH membranes were more than those of PP/ND membranes. Membranes embedded with 0.75 wt. % of neat and modified nanoparticles were used in a submerged membrane bioreactor (SMBR) system along with neat PP membrane. The results showed that critical flux values for neat PP, PP/ND and PP/ND-COOH membranes were 7, 18 and 22 L/(m2.h), respectively. Analysis of fouling mechanisms revealed that antifouling properties of 0.75 wt. % PP/ND-COOH membrane were higher than those of other two ones so that irreversible fouling ratio decreased from 88.9% for neat PP to 47.8% for PP/ND-COOH membrane.
Polymeric foams
Hossein Hazrati; Nader Jahanbakhshi; Mohammad Rostamizadeh
Abstract
In this study, the response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the preparation condition of polypropylene-grafted maleic anhydride (PP-g-MA) microporous membrane by thermally-induced phase separation (TIPS) method. A mixture of dibutyl phthalate ...
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In this study, the response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the preparation condition of polypropylene-grafted maleic anhydride (PP-g-MA) microporous membrane by thermally-induced phase separation (TIPS) method. A mixture of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) was used as diluent. The effect of polymer composition and quenching bath temperature on the morphology and performance of the fabricated microporous membranes was investigated by using RSM. Analysis of variance (ANOVA) was used to determine which variables and interactions between variables had a significant effect on our responses. The ANOVA revealed that the bath temperature was the most significant variable associated with porosity and pure water flux responses and the polymer concentration was the most significant variable associated with tensile response. The obtained results also showed that with increasing the polymer concentration and decreasing the quenching bath temperature, the membrane porosity and pure water flux decreased, whereas the membrane tensile increased. The regression equations were reasonably validated and used to predict and optimize the performance of PP-g-MA membranes within the limits of the variables. Finally, the maximum responses (flux of 115.6 L/m2h, porosity of 62% and tensile of 1.6 MPa) were obtained under the following conditions: polymer concentration of 28.5 wt% and temperature of 329 K. Further, comparison of laboratory-made and commercial membranes in a membrane bioreactor (MBR) system showed that the rate of membrane fouling was decreased by 4.2 times.
