Fabrication of High-Performance CNT Reinforced Polymer Composite for Additive Manufacturing by Phase Inversion Technique

Additive Manufacturing (AM) of polymer composites has enabled the fabrication of highly customized parts with notably mechanical properties, thermal and electrical conductivity compared to un-reinforced polymers. Employing the reinforcements was a key factor in improving the properties of polymers after being 3D printed. However, almost all the existing 3D printing methods could make the most of disparate fiber reinforcement techniques, the fused filament fabrication (FFF) method is reviewed in this study to better understand its flexibility to employ for the proposed novel method. Carbon nanotubes (CNTs) as a desirable reinforcement have a great potential to improve the mechanical, thermal, and electrical properties of 3D printed polymers. Several functionalization approaches for the preparation of CNT reinforced composites are discussed in this study. However, due to the non-uniform distribution and direction of reinforcements, the properties of the resulted specimen do not change as theoretically expected. Based on the phase inversion method, this paper proposes a novel technique to produce CNT-reinforced filaments to simultaneously increase the mechanical, thermal, and electrical properties. A homogeneous CNT dispersion in a dilute polymer solution is first obtained by sonication techniques. Then, the CNT/polymer filaments with the desired CNT content can be obtained by extracting the polymer’s solvent. Furthermore, optimizing the filament draw ratio can result in a reasonable CNT orientation along the filament stretching direction.

Antimicrobial Hydrophilic Membrane Formed by Incorporation of Polymeric Surfactant and Patchouli Oil

Membrane properties are highly affected by the composition of the polymer solutions that make up the membrane material and their influence in the filtration performance on the separation or purification process. This paper studies the effects of the addition of pluronic (Plu) and patchouli oil (PO) in a polyethersulfone (PES) solution on the membrane morphology, membrane hydrophilicity, and filtration performance in the pesticide removal compound in the water sample. Three types of membranes with the composition of PES, PES + Plu, and PES + Plu + patchouli oil were prepared through a polymer phase inversion technique in an aqueous solvent. The resulting membranes were then analyzed and tested for their mechanical properties, hydrophilicity, antimicrobial properties, and filtration performance (cross-flow ultrafiltration). The results show that all of the prepared membranes could reject 75% of the pesticide. The modification of the PES membrane with Plu was shown to increase the overall pore size by altering the pore morphology of the pristine PES, which eventually increased the permeation flux of the ultrafiltration process. Furthermore, patchouli oil added antimicrobial properties, potentially minimizing the biofilm formation on the membrane surface.

Copper Ions Removal by PSF-Si Spiral Wound Membranes of Different Porosity

Effluent discharged from various industries is one of the point sources of pollutions that affect the water quality. The effluent contains a high concentration of hazardous compounds of metal ions. Membrane technology using ultrafiltration membrane had proven successful in treating physical and organic impurities from water and wastewater. The importance of this study was to clarify the effectiveness of additive concentration in nanofiltration membrane for heavy metals removal. The physicochemical characteristics and copper ions removal efficiencies were determined for a different amount of silica extracted from sugarcane bagasse as an additive added to polysulfone polymer membranes. The PSF-Si membranes were fabricated via the phase inversion technique. The results show that silica in the formulation and fabrication of polysulfone membrane gives added value to membrane porosity, water content, and hydrophilicity. The most effective membrane in removing copper ions was the membranes with the lowest silica content, which is PSF-21 Si-2. The PSF-21 Si-2 membrane is hydrophilic, attracts a large amount of water, and gives a pure water flux of 56 L/m2hr to pass through the membrane. Moreover, the copper rejection increased from 92% to 98% as the copper concentration increased for the best membrane formulation PSF-21 Si-2.

Synthesis and Physicochemical Properties of Polyamideimide Membranes Containing ZIF-8 and CMS Particles for Potential Gas Separation Applications

The present study involves the fabrication and characterization of Polyamideimide (PAI) membrane holding ZIF-8 and CMS particles for potential gas separation applications. Zeolitic imidazolate frameworks-8 (ZIF-8) nanocrystals were prepared by a precipitation reaction with Zinc metal cluster and 2-methylimidazole, whereas the carbon molecular sieves (CMS) were synthesized by pyrolysis of polyamideimide (PAI) polymer. ZIF-8 and CMS particles were characterized comprehensively for the functional group, crystallinity, and morphological analyses. The successful formation of ZIF-8 nanocrystals was evident from the rhombic octahedron shape, and EDX confirms the presence of Zn metal cluster and methylimidazole linker. The ZIF-8 and CMS nanoparticles incorporated PAI membranes were prepared using phase inversion technique with varying loading wt.% of 1, 2, and 3%. PAI/ZIF-8 and PAI/CMS membranes cross-sectional morphology confirmed that synthesized nanoparticles were well embedded through the PAI membrane. The PAI/ZIF-8 (3 %) membrane, thin dense skin top layer, and well-defined honeycomb porous substructure were observed. Furthermore, the ZIF-8 and CMS particles incorporation have a beneficial impact on the mechanical properties of PAI at the low loading of nanoparticles. Thus, the inclusion of ZIF-8 and CMS particles in the PAI matrix positively altered the physicochemical properties of the resulting hybrid membranes, which could help them achieve remarkable gas permeance and selectivity.

Karakterisasi dan Kinerja Membran Polyethersulfone Termodifikasi Aditif Anorganik secara Blending Polimer

Recently, membrane technology has developed rapidly as a process for water treatment. The membrane process is in demand due to several advantages including being able to work at low temperatures, easier to operate and easy to scale up. Magnesium hydroxide (Mg(OH)2) is an inorganic compound that is inexpensive, non-toxic and hydrophilic, so it has the potential to be used as an additive in membrane fabrication. This study aims to determine the characteristics and performance (permeability and selectivity) of Polyethersulfone (PES) membrane modified with Mg(OH)2, using dimethyl Acetamide (DMAc) as solvent. The membrane was made by blending polymer with phase inversion technique and the characterization carried out included membrane morphological tests, functional group tests, water contact angle tests and evaluating membrane performance by measuring membrane selectivity and permeability. The results showed that the hydroxyl group contained in Mg(OH)2 was able to increase the hydrophilicity which was indicated by a decrease in the water contact angle on the modified membrane to 65o. The Mg(OH)2 additive acts as a pore-forming agent which can be seen in the changes in membrane morphology on the cross-section of the membrane surface. The performance of the membrane resulted in an increase in membrane permeability of 51 L/m2.hour.bar with humid acid rejection of 63%.

Karakteristik Membran Komposit Polietersulfon, Polivinilpirolidon dan Kitosan

Polyethersulfone (PES) is a membrane forming material that has many advantages but is hydrophobic, so it is necessary to add other materials, such as composite PES with Polyvinylpyrrolidone (PVP) and chitosan. The addition of PVP aims to change the nature of the PES membrane to be hydrophilic and the addition of chitosan aims to improve the mechanical properties of the polymer. The purpose of this study was to study the effect of adding PVP and chitosan to the characteristics of PES membranes. The membranes were made using a phase inversion technique by immersion precipitation with a concentration of 20% PES, 1% PVP, and chitosan were varied, namely 0% (M0 membrane), 1.5% (M1), 2% (M2), and 3% (M3). The results of the permeability test showed that the membranes M0, M1, M2, and M3 are classified as nanofiltration membranes with Lp values of 9.1237, 7.618, 6.9651, and 4.4077 L/m2.h.bar. The swelling degree value is 61,512; 103.111; 145,564; and 158.610% and the overall porosity value is 22.892; 32.360; 80.726; and 117.016%. The SEM test showed that the morphology of the membrane changed its structure as the concentration of chitosan increased. The FTIR test on the membrane showed that there were absorption bands, each of which identified its functional group.

Development of Multiwalled Carbon Nanotube-Reinforced Biodegradable Polylactic Acid/Polybutylene Succinate Blend Membrane

Currently, gas separation (GS) membranes are produced from petrochemical-based polymers, but their lifespan is severely impacting the environment. Therefore, there has recently been growing interest in developing ecofriendly biodegradable polymer-based GS membranes. This study developed a polylactic acid (PLA)/polybutylene succinate (PBS) blend composite membrane for GS using the dry/wet phase inversion technique. The influence of the multiwalled carbon nanotube (MWCNT) concentration in the PLA/PBS blend was studied by investigating tensile properties, porosity, percentage crystallinity, contact angle, and gas permeance. The obtained results demonstrate that the addition of MWCNT enhances the tensile strength, porosity, and percentage crystallinity, whereas it decreases the contact angle. The pure gas permeation was investigated at pressures of 2–4 bar at 25 °C. The gas permeation study revealed that the PLA/PBS blend with 0.5% wt. MWCNT enhanced the gas permeance and selectivity at 4 bar. The gas permeance acquired at 25 °C and 4 bar for PLA/PBS reinforced with MWCNT was highest in hydrogen followed by carbon dioxide, argon, and nitrogen. Additionally, a study of the membrane morphology illustrated the uniform dispersion of MWCNT in the PLA/PBS blend. The investigation concluded that membranes containing MWCNT are capable of separating gases at the molecular level, thereby reducing energy consumption.

Visible Light-Driven GO/TiO2-CA Nano-Photocatalytic Membranes: Assessment of Photocatalytic Response, Antifouling Character and Self-Cleaning Ability

Photocatalysis and membrane technology in a single unit is an ideal strategy for the development of wastewater treatment systems. In this work, novel GO (x wt%)/TiO2-CA hybrid membranes have been synthesized via a facile non-solvent induced phase inversion technique. The strategy aimed to address the following dilemmas: (1) Effective utilization of visible light and minimize e−/h+ recombination; (2) Enhanced separation capability and superior anti-fouling and self-cleaning ability. The experimental results reveal that the integration of nano-composite (GO/TiO2) boosts the membrane properties when compared to pristine CA and single photocatalyst employed membrane (GO-CA and TiO2-CA). The effect of GO content on the properties of the photocatalytic membrane has been determined by utilizing three different ratios of GO, viz. 0.5 wt%, 1 wt%, and 2 wt% designated as NC(1)-CA, NC(2)-CA, and NC(3)-CA, respectively. Amongst them, NC(3)-CA membrane showed state-of-the-art performance with an elevated photocatalytic response (four times higher than pristine CA membrane) toward methyl orange. Moreover, the water flux of NC(3)-CA membrane is 613 L/m2h, approximately three times higher than bare CA membrane (297 L/m2h), while keeping the MO rejection high (96.6%). Besides, fouling experiments presented the lowest total and fouling resistance ratios and a higher flux recovery ratio (91.78%) for the NC(3)-CA membrane, which endows the membrane with higher anti-fouling and self-cleaning properties. Thus, NC(3)-CA membrane outperforms the other as synthesized membranes in terms of separation efficiency, visible light photo-degradation of pollutant, anti-fouling and self-cleaning ability. Therefore, NC(3)-CA membrane is considered as the next generation membrane for exhibiting great potential for the wastewater treatment applications.

FORMULATION, DEVELOPMENT AND EVALUATION OF TOPICAL INTRADERMAL DRUG DELIVERY SYSTEM FOR ANTI-ACNE PRODUCT

The objective of the present study was to explore the anti-acne activity of herbal drug extracts of curcumin by making complexes with varying concentrations of soya lecithin using the phase inversion technique. The preformulation studies were performed and indicated that using the resultant formulation FIM4 shows the maximum potency outcomes. The characterization and evaluation were carried using Fourier Transform Infrared Spectroscopy (FTIR) and using various parameters such as appearance, texture, pH determination, viscosity, spreadability, stability, drug content, saponification value, irritation, antibacterial activity and in vitro diffusion. From the study, it was concluded that the optimized formulation FIM4 show the best resulting potency with antimicrobial properties.