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The main focus of the work is on developing a new class of hybrid composite with polyester as the continuous phase and micro-sized hexagonal boron nitride (hBN) and short sisal fibre as the discontinuous phases. The effect of loading of discontinuous phases on the different properties of the composites is analysed experimentally. The incorporation of either of the discontinuous phases unwillingly increases the void content and water absorption rate. With hBN content, the density increases, whereas, with sisal fibre content density decreases. The hybrid combination of fillers successfully improves the glass transition temperature (Tg) and coefficient of thermal expansion (CTE) of the polymeric resin. The maximum Tg reported is 106.2°C and the minimum CTE reported is 51.7 × 10−6/oC for the polyester reinforced with 40 wt. % hBN and 5 wt. % sisal fibre. The incorporation of hBN upsurges the thermal conductivity but also increases the dielectric properties. The dielectric properties gainfully reduce with the addition of sisal fibre. Dielectric properties also decrease with an increase in the working frequency. The incorporation of sisal fibre slightly reduces the thermal conductivity of the composites. The mechanical properties like tensile strength and flexural strength of the hybrid composite increase when the combination of hybrid fillers is judicially selected, whereas, the compressive strength and hardness of the composite increase with filler/fibre loading with maximum 131.4 MPa and 80.0 Shore D number, respectively. Due to the improved overall properties, the composite material under investigation can find its potential application in various microelectronic applications. [ABSTRACT FROM AUTHOR]

The current study aims to examine the influence of treating micro-sized walnut shell particulates (WSP) with an aqueous solution of sodium hydroxide (NaOH) at the varied concentration on the physical and mechanical properties of a newly developed epoxy composite. Three sets of epoxy/WSP composites are prepared, i.e. Set A is for composites prepared with raw WSP, set B and set C is for composites prepared with treated WSP with 2 and 4 moles NaOH aqueous solution, respectively. For each set, four samples are fabricated for different WSP content (5, 10, 15, and 20 wt. %). It has been observed that the density of the composites reduces as the content WSP increases over the entire range of filler content. Against that, the volume of voids increases with WSP loading. Similarly, the water intake of composites also increases with filler loading. Mechanical properties like compressive strength, hardness, tensile and flexural modulus increase as a linear function of filler content whereas, tensile strength and flexural strength increase up to 10 wt. % of filler and decreases thereafter. Further, it is found that when WSP is modified with a 2-moles NaOH aqueous solution improves all the properties under investigation. Though, WSP treated with a 4-mole NaOH aqueous solution slightly deteriorates the properties of the material due to the excess concentration of NaOH. [ABSTRACT FROM AUTHOR]

The current study aims to examine the influence of surface‐modified micro‐sized walnut shell particulates (WSP) with an aqueous solution of sodium hydroxide (NaOH) on epoxy composites. For that, epoxy/WSP composites are prepared by varying the WSP content up to 20 wt%. In this investigation, the physical properties (surface morphology, density, voids percentage, water uptake), mechanical properties (tensile, flexural, compressive, hardness), and sliding wear behavior of the composites are reported. From the micrographs, it is clear that WSP established good adhesion with the epoxy matrix. Further, it is found that the density, void content, water intake capacity, compressive strength, and hardness increase with WSP loading. Against that, the tensile and flexural strength is somewhat reduced at higher filler loading. Sliding wear tests are performed as per L25 Taguchi's orthogonal array. From the analysis, it is observed that WSP content is the most significant factor and sliding distance is the least significant factor for minimizing the wear rate. For analyzing the sliding wear performance under varied conditions, a prediction model is proposed using an artificial neural network to forecast the sliding wear rate of epoxy/WSP composites over a wide range of experimental domains. [ABSTRACT FROM AUTHOR]

Kota stone dust (KSD) and fly ash (FA) are the wastes generated from the construction industry and thermal power plant, respectively. In the present work, a novel hybrid composite is developed to utilize KSD and FA as reinforcing phases in the epoxy matrix. The hand lay‐up method is adopted for the fabrication of 12 sets of samples. Four sets are prepared with single filler KSD and eight samples are prepared with a hybrid combination of KSD and FA. The prepared samples are undergone physical and mechanical tests. To understand the compatibility between filler‐matrix and visualize the dispersion of fillers in epoxy, micrographs are taken using the scanning electron microscope. The density and void contents of the material increases with an increase in filler content. The maximum water absorption measured is 0.96% for the combination of epoxy with 40 wt% KSD and 10 wt% FA. From mechanical testing, maximum tensile strength and flexural strength obtained is 34.4 MPa and 65.4 MPa, respectively, for a combination of epoxy with 20 wt% KSD and 5 wt% FA. Compressive strength and hardness increase with either of the content of the filler and reaches 116.28 MPa and 104 Shore D number, respectively, with 40 wt% KSD and 10 wt% FA. From experimentation, it was found that mechanical properties of the hybrid composites are better as compared to that of single filler composites though physical properties are slightly compromised by hybridization of fillers. [ABSTRACT FROM AUTHOR]

In the present work, a new class of polymer composite is developed using walnut shell powder (WSP) as particulate filler in the epoxy matrix. Three different sizes of WSP are used for preparing three different sets of composites. The particle size selected is 50-micron, 75-micron, and 100-micron. In each set of composites with different particle size, four compositions i.e., 5 wt. %, 10 wt. %, 15 wt. % and 20 wt. % of the WSP is fabricated. All prepared composites have undergone testing to study the behavior of the material under mechanical loading. The different mechanical tests performed are the tensile test, flexural test, compressive test and hardness test. From the experimentation, the inclusion of WSP appreciably alters the different mechanical properties of epoxy. With the increase in the content of filler, an appreciable increase in the value of hardness and compressive strength is observed. Though, it has been seen that the tensile strength and flexural strength of the material is compromised slightly when the content of WSP increases beyond a certain limit. Further, it is observed that composites fabricated with smaller size particles give improved mechanical properties as compared to their counterparts. [ABSTRACT FROM AUTHOR]

This work investigates a composite prepared with polyester and hexagonal boron nitride (hBN) in terms of the properties required in the material for microelectronics applications. The influence of filler loading and the surface treatment of hBN with a silane coupling agent (γ‐aminopropyl triethoxy silane) is studied. It has been observed that the silane‐modified hBN improves the compatibility and adhesion with the matrix as verified by SEM images. The experimental investigation reveals that the addition of hBN in polyester unwillingly rises the density, voids content, and water absorption rate. Though, the increment is limited with surface‐modified hBN. The material's mechanical properties improve with filler loading over a particular range of filler loading. The material's thermal conductivity and glass transition temperature increase with hBN content, whereas the coefficient of thermal expansion reduces. Polyester when filled with 40 wt% of the silane‐hBN, the thermal conductivity improves around six times that of unfilled polyester. The dielectric properties are marginally augmented with filler loading whereas, the increase in frequency results in the reduction of dielectric properties. It can be observed from the overall experimental analysis that the developed material can be used in different microelectronic applications. Highlights: A new class of composite is developed with polyester and raw/modified hBN.Composite with modified hBN shows improved physical/mechanical properties.Thermal properties of polyester improved appreciably with treated hBN.The dielectric properties of composites remain well within the range.The fabricated composites are recommended for microelectronics applications. [ABSTRACT FROM AUTHOR]