Development Of Core Layer Materials Using Particulate Filled Epoxy Composites [TK7870.15. T261 2008 f rb].

Kajian ke atas epoksi terisi pengisi partikulat ini adalah terdiri daripada enam peringkat. Bahagian pertama kajian ini melibatkan pengkajian mengenai kesan pengisi-pengisi partikulat: The research on epoxy filled with particulate fillers composites consist of six parts. The first part of the study is to investigate the effect of types particulate fillers

Effect of Heat Assisted Bath Sonication on the Mechanical and Thermal Deformation Behaviours of Graphene Nanoplatelets Filled Epoxy Polymer Composites

Graphene nanoplatelets (GNP) filled epoxy composites ranged from 0.2 to 5 vol.% were prepared in this study using simple heat assisted bath sonication for better GNP dispersion and exfoliation. The effects of GNP filler loading via heat assisted bath sonication on the mechanical properties and thermal deformation behaviour were investigated. Improvements on flexural strength and fracture toughness up to 0.4 vol.% filler loading were recorded. Further addition of GNP filler loading shows a deteriorating behaviour on the mechanical properties on the composites. The bulk electrical conductivity of the epoxy composites is greatly improved with the addition of GNP filler loading up to 1 vol.%. The thermal expansion of epoxy composites is reduced with the addition of GNP; however poor thermal stability of the composites is observed

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Treated Nypa fruticans Husk-filled Regenerated Cellulose Biocomposite Films

The effects of filler content and methacrylate acid (MAA) treated Nypa fruticans husk (NFH) on the mechanical properties, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and morphology of NFH regenerated cellulose (RC) biocomposite films were investigated. Ionic liquid containing 8 wt% of lithium chloride (LiCl)/N,N-dimethylacetamide (DMAc) was used to dissolve microcrystalline cellulose (MCC) and NFH to produce NFH RC biocomposite films. Methacrylate acid was used as a modifying agent on the NFH to promote better mechanical and thermal properties for the resulting NFH RC biocomposite films. The results showed that the tensile strength, Young’s modulus, crystallinity index (CrI), moisture content, and thermal stability of the untreated NFH RC biocomposite films increased with increasing NFH content up to 3 wt% and decreased with further increments. The MAA-treated NFH showed improved tensile strength and Young’s modulus compared with the untreated NFH RC biocomposite films. The presence of MAA enhanced the crystallinity index (CrI), moisture resistance, and thermal stability of the NFH RC biocomposite films. Good interfacial interaction between the NFH and RC matrix was proven by scanning electron microscopy (SEM)

Chemical Modification of Nypa fruticans Filled Polylactic Acid/Recycled Low-density Polyethylene Biocomposites

Nypa fruticans (NF) is a lignocellulosic material belonging to the family Palmae or Arecaceae. Effects of NF content and chemical modification using methyl methacrylate (MMA) on tensile, thermal, and morphological properties of biocomposites were investigated. The results showed that the addition of NF decreased the tensile strength, elongation at break, and crystallinity, but increased the Young’s modulus, of biocomposites. Moreover, the addition of NF increased the thermal stability. Meanwhile, the tensile strength and Young’s modulus of the biocomposites treated with MMA were higher than the untreated biocomposites. The treated biocomposites exhibited higher thermal degradation temperature and crystallinity compared to the untreated biocomposites. The morphology study of the tensile-fractured surfaces of biocomposites indicated that chemical modification with MMA enhanced the interfacial interaction between NF and the PLA/rLDPE matrix

Porous Epoxy: Effect of Mixing Sequences (ELH versus EHL) Using Toluene as Extraction Medium via Ultrasonic Technique

Porous epoxy was fabricated using natural rubber latex (NRL) as the void template. In this study, two mixing sequences were selected: epoxy, hardener, and then latex (EHL) and epoxy, latex, and then hardener (ELH). The extraction process was carried out to extract the latex particles from the cured epoxy sample using toluene as extraction medium with ultrasonic technique for 1 hour. The formation of porous structure in epoxy system is dependent essentially on the amount of latex removed from the epoxy matrix. As expected, the density results showed lower values in the porous epoxy in ELH mixing sequences. More porous structure in epoxy was obtained which was proven by the increasing in porosity % which has led to lowering of the value in dielectric constant which is preferred for electronic packaging application. However, it also caused a decrease in flexural strength and modulus

Thermal Degradation of Photoluminescence Poly(9,9-dioctylfluorene) Solvent-Tuned Aggregate Films

The progression of the green emission spectrum during the decomposition of polyfluorenes (PFs) has impeded the development and commercialization of the materials. Herein, we constructed a solvent-tuned aggregated PFO film with the aim of retarding the material&rsquo;s thermal degradation behavior which causes a significant decline in optical properties as a result of phase transformation. The tuning of the aggregate amount and distribution was executed by applying a poor alcohol-based solvent in chloroform. It emerges that at a lower boiling point methanol evaporates quickly, limiting the aggregate propagation in the film which gives rise to a more transparent film. Furthermore, because of the modulated &beta;-phase conformation, the absorption spectra of PFO films were red-shifted and broadened. The increase in methanol percentage also led to a rise in &beta;-phase percentage. As for the thermal degradation reactions, both pristine and aggregated PFO films exhibited apparent changes in the UV-Vis spectra and PL spectra. In addition, a 97:3 (chloroform:methanol) aggregated PFO film showed a more defined emission spectrum, which demonstrates that the existence of &beta;-phase is able to suppress the unwanted green emission

Thermal Degradation of Photoluminescence Poly(9,9-dioctylfluorene) Solvent-Tuned Aggregate Films

The progression of the green emission spectrum during the decomposition of polyfluorenes (PFs) has impeded the development and commercialization of the materials. Herein, we constructed a solvent-tuned aggregated PFO film with the aim of retarding the material’s thermal degradation behavior which causes a significant decline in optical properties as a result of phase transformation. The tuning of the aggregate amount and distribution was executed by applying a poor alcohol-based solvent in chloroform. It emerges that at a lower boiling point methanol evaporates quickly, limiting the aggregate propagation in the film which gives rise to a more transparent film. Furthermore, because of the modulated β-phase conformation, the absorption spectra of PFO films were red-shifted and broadened. The increase in methanol percentage also led to a rise in β-phase percentage. As for the thermal degradation reactions, both pristine and aggregated PFO films exhibited apparent changes in the UV-Vis spectra and PL spectra. In addition, a 97:3 (chloroform:methanol) aggregated PFO film showed a more defined emission spectrum, which demonstrates that the existence of β-phase is able to suppress the unwanted green emission

Effect of Printing Parameters on Tensile, Dynamic Mechanical, and Thermoelectric Properties of FDM 3D Printed CABS/ZnO Composites

Fused deposition modelling (FDM) has been widely used in medical appliances, automobile, aircraft and aerospace, household appliances, toys, and many other fields. The ease of processing, low cost and high flexibility of FDM technique are strong advantages compared to other techniques for thermoelectric polymer composite fabrication. This research work focuses on the effect of two crucial printing parameters (infill density and printing pattern) on the tensile, dynamic mechanical, and thermoelectric properties of conductive acrylonitrile butadiene styrene/zinc oxide (CABS/ZnO composites fabricated by FDM technique. Results revealed significant improvement in tensile strength and Young’s modulus, with a decrease in elongation at break with infill density. Improvement in dynamic storage modulus was observed when infill density changed from 50% to 100%. However, the loss modulus and damping factor reduced gradually. The increase of thermal conductivity was relatively smaller compared to the improvement of electrical conductivity and Seebeck coefficient, therefore, the calculated figure of merit (ZT) value increased with infill density. Line pattern performed better than rectilinear, especially in tensile properties and electrical conductivity. From the results obtained, FDM-fabricated CABS/ZnO showed much potential as a promising candidate for thermoelectric application