Mechanical properties of epoxy resin toughened with cornstarch

We investigated the effect of starch modification on the mechanical properties of phenolic epoxy resin (EP). Corn starch admixture of 2.5, 5, 7.5, and 10 wt% were added into the EP. The tensile strength, elongation at break, and elastic modulus of different corn starch contents were compared. The containing of corn starch showed a positive effect on the toughness of the epoxy but showed little effect on strength when the additive content was less than 10 wt%. The strength and elastic modulus increased first and then decreased with the increase in starch content and reached their maximum values at a content of 2.5 wt%. The enhancement effect might be due to corn starch’s mechanical properties, dispersibility, and interfacial interaction. With the increase in starch content, starch granules quickly contact each other, causing self-aggregation sedimentation and a decrease in strength and elastic modulus. The scanning electron micrographs of the toughened EP specimens showed ductile failure because of the starch particles. The surface morphology of the blend resin specimens was full of staggered and stepped cracks caused by the shearing damage, which is shown by obvious plastic fracture characteristics with plastic deformation ability. The initiation of micro-cracks in the EP matrix was induced by the incorporation of starch particles, which caused localized stepped shear damage in the matrix. More energy would be absorbed during this process, and the toughness of the EP would be enhanced. It is recommended that the best corn starch content should be 2.5 wt% to obtain excellent strength and good toughness.

Manufactures of bio‐degradable and bio‐based polymers for bio‐materials in the pharmaceutical field

In recent years, bio‐based polymers have emerged as an alternative to petroleum‐based polymers in various industries. The bio‐based materials are made from raw materials originating from natural sources, such as starch, cellulose, chitin, or bio‐degradable synthetic polymers (i.e., polycaprolactone and polylactic acid). In spite of several desirable properties of biodegradable polymers, for example, fully renewable, non‐toxic. Some properties like melt and impact strength, thermal stability, permeability, and so forth, still do not meet the demands for end‐use applications. One way to improve the properties of biopolymers and greatly enhance their commercial potential is to incorporate nanosized reinforcement in the polymer. The access of nano‐carriers to smart polymeric and bio‐materials are limited by polymerization methods. Bio‐polymers are considered an alternative to petroleum‐based fibers. These are directly produced by organisms. Smart nanoparticles are used in different medicines and their applications are size‐dependent. Among the different techniques used for sensitivity, selectivity, and interactions among the nanoparticles. More so, different approaches were found for polymerization. Methodologies such as the preparation of nano‐gels, bio‐degradable, and bio‐polymers manufacturing in the pharmaceutical field are discussed in detail. Their applications, properties in gene delivery, smart imaging, and multivalency approach are also highlighted.

Synthesis and modification of silica‐based epoxy nanocomposites with different sol–gel process enhanced thermal and mechanical properties

This research article describes the results of nano‐silica composites filled with different epoxy contents containing nano‐SiO2 particles from (5–25 wt%). Reinforcing hybrid composites enhance thermal and mechanical properties to achieve vital and sustainable products. Silica‐based nanocomposites with high purity were prepared and used for the surface modification of nanosized silica particles. The surface structure's composition and physical properties of modified nano‐SiO2 particles were characterized through Fourier transferred infrared spectrometer, X‐ray photoelectron spectroscopy, thermogravimetric analyzer, and scanning electron microscopic. Silica‐based nanocomposites were prepared by incorporating of modified nano‐SiO2 as an enhancing filler. The morphology of fracture surface and dynamic mechanical properties were investigated. Results showed that the silica‐based epoxy nanocomposites are bearing a long chain structure that could improve the compatibility of silica nanocomposites with epoxy resin and contribute to a better dispersion state in the matrix, which enhanced the overall performance of epoxy‐cured products.