Graphene-Based Composite Membrane Prepared from Solid Carbon Source Catalyzed by Ni Nanoparticles

Emerging as a light, flexible and highly thermally conductive material, graphene-based membranes have attracted extensive attention in thermal management field. However, the preparation of high-quality graphene-based membranes usually involves complex processes and thermal annealing at ultra-high temperature, which limits their large-scale application in thermal management field. In our study, reduced graphene oxide-Ni-hydroxypropyl methyl cellulose (RGO-Ni-HPMC) composite membrane was prepared from catalytic pyrolysis of hydroxypropyl methyl cellulose (HPMC) with Ni nanoparticles to generate multilayer graphene and form phonon transport channels between adjacent graphene layers. Further, our study shows that the RGO-Ni-HPMC composite membrane has a good heat dissipation effect at the hot spots at high temperature. The average temperature of hot spots is reduced by 11.5 °C. It is expected to solve the heat dissipation problem of high-power electronic equipment.

FTIR INVESTIGATION ON CRYSTALLINITY OF HYDROXYPROPYL METHYL CELLULOSE-BASED POLYMERIC BLENDS

Two series of polymeric blends have been prepared based on hydroxypropyl methyl cellulose (HPMC)/polyacrylic acid (PAA) (1:1, 1:2, 1:3, 1:4) and HPMC/sodium alginate (SA) (1:30, 2:30, 3:30, 4:40) and investigated by Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). IR analysis confirmed the interaction between the polymeric components in the blend and the degree of structural organization. Crystallinity changes in the blends were observed as a function of a number of experimental parameters, such as temperature, composition and HPMC concentration, by determining the quantitative crystallinity indexes: Total Crystallinity Index (TCI), Lateral Order Index (LOI) and Hydrogen Bond Index (HBI).

Optimasi Sintesis Hydroxypropyl Methyl Cellulose (HPMC) dari Kulit Koro Pedang Putih (Canavalia ensiformis L. (DC)

Kulit koro pedang putih dapat digunakan sebagai sumber selulosa. Salah satu alternatif untuk meningkatkan aplikasi selulosa adalah dengan memodifikasi selulosa menjadi produk turunan selulosa yaitu Hydroxypropyl Methyl Cellulose (HPMC). Tujuan dari penelitian ini adalah melakukan optimasi terhadap sintesis dan karkaterisasi HPMC dari selulosa kulit koro pedang putih. Proses optimasi didahului dengan kajian literatur untuk menentukan kisaran titik percobaan dengan variabel terikat berupa molar subtitusi (MS) dan Derajat Subtitusi (DS). Diperoleh titik percobaan dengan variasi konsentrasi NaOH (5, 22,5, dan 40%), variasi Dimetil Sulfat (DMS) (40, 80, dan 120%), dan variasi Proilen Oksida (PO) (80, 120, dan 160%). Kemudian optimasi sintesis HPMC dilakukan dengan mengunakan Box-Behnken design (BBD) lalu dianalisis menggunakan Response Surface Methodology (RSM) Berikutnya HPMC dikarakterisasi meliputi molar subtitusi (MS), Derajat Subtitusi (DS), water holding capacity (WHC), oil holding capacity (OHC), lightness, rendemen, kristalinitas dan spektra FT-IR untuk mengetahui gugus fungsi HPMC. Hasil optimasi sintesis HPMC dari selulosa kulit koro pedang putih berdasakan RSM diperoleh titik optimum pada konsentrasi NaOH 23,11%, DMS 43,4% dan PO 81,8%. dengan karakterisasi kadar air 9,04% (wb); MS 0,15; DS 1,18; WHC 2,20 g/g; OHC 2,09 g/g; lightness 90,93; rendemen 114,78% dan kristalinitas 64%. Spektra FT-IR HPMC koro pedang putih terbaca pada bilangan gelombang 2924 cm-1 (CH dan CH2 Streching), 1373 cm-1 (CH3 Bonding), 1118 cm-1 (C-O-C), 1319 cm-1 (O-H Plane Bonding) dan 848, 68 cm-1 (C-O-C pada 1,4 β glikosidic linkage) yang merupakan ciri khas dari gugus fungsional HPMC.

Controlled Release of Curcumin from HPMC (Hydroxypropyl Methyl Cellulose) Co-Spray-Dried Materials

In order to achieve the controlled release of curcumin, HPMC (hydroxypropyl methyl cellulose) was spray dried with curcumin and lactose. The spray-dried materials were pressed into tablets with a diameter of 8 mm, and their release characteristics in vitro were measured. In vitro experiments showed that the release of curcumin from the HPMC mixture was significantly slower due to the sustained-release property of HPMC as a typical excipient. The release profile of curcumin from the HPMC mixture was relatively stable for a controlled release. SEM images show that the HPMC co-spray-dried powders have crumpled surfaces due to the large molecular weight of HPMC. DSC, XRD, FTIR, N2 adsorption, and TGA have been measured for the spray-dried curcumin materials. This work indicates that HPMC can be used as a controlled-release excipient for curcumin preparations.