Effect of processing conditions on mechanical and viscoelastic properties of biocomposites

Polypropylene hybrid composites: Effect of reinforcement of sisal and carbon fibre on mechanical, thermal and morphological properties

Polypropylene (PP)/sisal fibre (SF)/carbon fibre (CF) hybrid composites were prepared by melt blending process at a variable weight percentage (wt%) of carbon: sisal fibre loading (20:10, 15:15, 10:20, and 5:25). MA-g-PP (MgP) as a compatibiliser was used to improve the dispersion of the fibres within the PP matrix. The composites were subjected to mechanical tests to optimize the fibre content of CF: SF. Incorporation of 20 wt% of CF and 10 wt% of SF with 5 wt% MgP resulted in higher mechanical performance of about 67.02 and 112% over that of PP/SF composite. Similarly, the impact strength was found to be optimum which enhanced to the tune of 39.62% as compared with PP/SF composites. Halpin Tsai model was used to compare the theoretical tensile modulus of PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites with experimental evaluated values. Fracture toughness parameters such as K IC (critical stress intensity factor) and G IC (critical strain energy release rate) are determined for PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites and compared by using single edge notch test. DSC study showed higher melting temperature (T m ) of PP/SF/CF/MgP composites as compared to PP revealing the enhancement in thermal stability. TGA/DTG study revealed the synergistic effect of the hybrid composite thus confirming the hybridisation effect of the system. DMA study showed that the hybridisation of CF and SF within the matrix polymer contributes to an increase in the storage modulus (Eʹ). Morphological observation by SEM confirmed that the carbon fibres and sisal fibres are well uniformly dispersed within the PP matrix, in the presence of MgP.

Impact of Surface Modification and Nanoparticle on Sisal Fiber Reinforced Polypropylene Nanocomposites

The use of plant fibers, polymer, and nanoparticles for composite has gained global attention, especially in the packaging, automobile, aviation, building, and construction industries. Nanocomposites materials are currently in use as a replacement for traditional materials due to their superior properties, such as high strength-to-weight ratio, cost effectiveness, and environmental friendliness. Sisal fiber (SF) was treated with 5% NaOH for 2 hours at 70°C. A mixed blend of sisal fiber and recycled polypropylene (rPP) was produced at four different fiber loadings: 10, 20, 30, and 40 wt.%, while nanoclay was added at 1, 3, and 5 wt.%. Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer for all composites prepared except the untreated sisal fibers. The characterization results showed that the fiber treatment, addition of MAPP, and nanoclay improved the mechanical properties and thermal stability and reduced water absorption of the SF/rPP nanocomposites. The tensile strength, tensile modulus, and impact strength increased by 32.80, 37.62, and 5.48%, respectively, when compared to the untreated SF/rPP composites. Water absorption was reduced due to the treatment of fiber and the incorporation of MAPP and nanoclay.

Preparation and Properties of Biodegradable Film Composites Using Modified Cellulose Fibre-Reinforced with PVA

Cellulose has a potential to become a key resource in the development of biodegradable film composites. In this work, cellulose was modified by using 2-(Trifluromethyl)benzoylchloride by base-catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by film casting method using modified cellulose with Poly(vinyl alcohol) in different compositions. The film composites were characterized by mechanical, moisture absorption, gas barrier, and biodegradable properties. Obtained films have shown transparency and flexibility and displayed good mechanical properties. Film composites also showed good biodegradability. Better barrier properties showed by film composites as the percentage of modified cellulose increased. This indicates the importance of modified cellulose as a reinforcing agent. After evaluating these properties of film composites, we came to conclusion that these biocomposites can be used to membrane and packaging applications.