Mardi Santoso

Biopolymer-based electrolyte membranes from chitosan incorporated with montmorillonite-crosslinked GPTMS for direct methanol fuel cells

A composite membrane was fabricated from biopolymer chitosan and montmorillonite (MMT) filler as an alternative membrane electrolyte for direct methanol fuel cell (DMFC) application. To first improve the organic–inorganic interfacial morphology, the pristine MMT was pre-treated using 3-glicidoxy propyltrimethoxysilane (GPTMS) surface modifier to produce organophilic MMT (O-MMT). The GPTMS modified MMT was mixed with chitosan in acetic acid solution and cast into membranes. SEM images and FTIR analysis showed that the O-MMT was successfully incorporated into the chitosan polymer matrix. Water and methanol uptake of the Ch/O-MMT composite membranes decreased with increasing O-MMT loadings, but the ion exchange capacity (IEC) value increased. The Ch/O-MMT with 5 wt% O-MMT loading exhibited the best methanol permeability and proton conductivity characteristics among the other Ch/O-MMT membranes, which were 3.03 × 10−7 cm2 s−1 and 4.66 mS cm−1, respectively. All the results obtained from this study can be used to conclude that the chitosan membrane with O-MMT filler is a promising high performance PEM candidate for DMFC application.

Characteristic Changes in the Aroma Profile of Patchouli Depending on Manufacturing Process

Patchouli is used as an incense material and essential oil. The characteristic odor of patchouli leaves results from the drying process used in their production; however, there have to date been no reports on the changes in the odor of patchouli leaves during the drying process. We investigated the aroma profile of dried patchouli leaves using the hexane extracts of fresh and dried patchouli leaves. We focused on the presence or absence of the constituents of the fresh and dried extracts, and the differences in the content of the common constituents. Fourteen constituents were identified as characteristic of dried patchouli extract odor by gas chromatography-olfactometry analysis. The structures of seven of the 14 constituents were determined by gas chromatography-mass spectrometry (α-patchoulene, seychellene, humulene, α-bulnesene, isoaromadendrene epoxide, caryophyllene oxide, and patchouli alcohol). The aroma profile of the essential oil obtained from the dried patchouli leaves was clearly different from that of dried patchouli. The aroma profile of the essential oil was investigated by a similar method. We identified 12 compounds as important odor constituents. The structures of nine of the 12 constituents were determined by gas chromatography-mass spectrometry (cis-thujopsene, caryophyllene, α-guaiene, α-patchoulene, seychellene, α-bulnesene, isoaromadendrene epoxide, patchouli alcohol, and corymbolone). Comparing the odors and constituents demonstrated that the aroma profile of patchouli depends on the manufacturing process.

Hubungan antara kekonduksian proton, sifat hidrofil dan kestabilan termal atas membran komposit kitosan/montmorillonit dengan modifikasi GPTMS dan prestasinya dalam sel bahan api metanol langsung

Chitosan based inorganic hybrid membrane is a promising organic–inorganic hybrids for the development of high performance proton exchange membrane (PEM). The immobilization of modified montmorillonite (MMT) using GPTMS within chitosan matrix would possess superior physicochemical characteristics due to more hydrogen bonding formation introduced by GPTMS. Therefore, higher number hydrogen bond formation can be expected in Ch/MMT-GPTMS membrane rather than in pure Ch membrane. A fully hydrated membrane at elevated temperatures is desirable for efficient proton conduction in the membranes. It remains a critical challenge to maintain proper hydration of the membranes for the operation of the direct methanol fuel cell (DMFC). The microstructure obtained by SEM for composites showed that filler was successfully incorporated and relatively well dispersed in the chitosan polymer matrix. The role of surface modification of MMT filler by GPTMS have increase the functional group that can form hydrogen bonding which suitable for interaction with water. High water uptake is favourable for high performance PEM to facilitate great numbers of protons hopping and diffusion through the membrane. In addition, greater hydrogen bonding formation would lead to the tighter packing of composite membrane, resulting in higher bonding strength and higher thermal resistance. The Ch/MMT-GPTMS composite membrane with 5 wt% filler loading exhibited the best proton conductivity are 4.66 mScm-1, with water contact angle value of 64.73°. A maximum power density of 0.24 mWcm-2 was obtained with a 2M methanol feed. The relationship of water contact angle, water upake, membrane swelling, thermal stability, and proton conductivity shown suitable trend, it means that all quality of them are related to the hydrophilicity properties.

Membran campuran daripada poli(eugenol sulfonat) dan polieterimida sulfonat yang menjanjikan untuk sel bahan api metanol langsung

A new polymeric membrane blended from sulfonated polyetherimide (SPEI) and poly(eugenol sulfonate) (PES) was prepared as proton exchange membrane (PEM) for direct methanol fuel cell (DMFC). The membrane was characterized by Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA) and Scanning Electronic Microscopy (SEM). Ion exchange capacity (IEC), proton conductivity, methanol barrier, water uptake, water contact angle and mechanical strength of the membrane was also being determined. The new PES/SPEI membrane with 3 wt.% PES and 20 wt.% SPEI show higher IEC, water uptake, proton conductivity and methanol barrier properties as compared to Nafion 117 membrane. As a conclusion, the results indicate that the SPEI/PES membrane has potential to be employed as PEM for DMFC application.