Search

In this study, PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films were fabricated via solution casting method. By testing the film density, solubility, water contact angle and water vapor permeability, the PLA nanocomposite films, the comprehensive performances of the nanocomposites were analysed. The outcomes demonstrated that maximum film density of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films increased gradually with the increasing of nanofiller loadings. Moreover, the incorporation of TiO2 and HNTs-TiO2 significantly decreased the water vapor transmittance rate of the nanocomposite films with a slight priority to the addition of HNTs-TiO2, the water solubility was significantly improved with the addition of both nanofillers. Furthermore, the barrier properties were developed with the addition of both TiO2 and HNTs-TiO2 especially after the addition of low nanofiller loadings. Overall, the performance of the PLA/HNTs-TiO2 nanocomposite films was better than that PLA/TiO2 film. Nevertheless, both of the PLA nanocomposite samples achieved the requests of food packaging applications.

Polylactic acid (PLA) nanocomposite samples with different properties like mechanical, thermal, barrier and antibacterial properties are good candidates as packaging biomaterials. Unique PLA/TiO2 and PLA/HNTs-TiO2 nanocomposite samples were fabricated by solution casting method. The mechanical and antibacterial properties of PLA/TiO2 and PLA/HNTs-TiO2 samples were investigated with comparing to the pristine PLA film as a control sample. PLA nanocomposite samples with TiO2 nanofillers showed poorer mechanical properties while PLA films with PLA/HNTs-TiO2 showed unique developments, which tensile strength improved by 46% with the incorporation of 5 wt%. The PLA nanocomposites showed a high efficiency to both Gram positive and Gram negative bacteria, significant antibacterial effect being proved after first week elapsed time by comparing to the control sample (presenting no antibacterial effect). By considering the multifunctional characteristics of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites, the samples produced by solution casting can be considered a favourable alternative as environmental-friendly packaging materials.

In this study, biodegradable polylactic acid (PLA)/chitosan (Cs) composites were produced via melt compounding and compression molding techniques. Various chitosan loadings of 2.5, 5, 7.5 and 10 parts per hundred parts of polymer (php) were incorporated into PLA and its effects on thermal, water absorption kinetics, tensile and morphological characteristics were investigated systematically. Thermal analysis indicated that an increase in chitosan loading of up to 10 php enhanced the crystallinity percentage (χc) of neat PLA to an extent of 51%, yet reduced the thermal stability of the resulting biocomposites. The kinetic study results revealed that water absorption of PLA/Cs biocomposites approached the Fickian diffusion behavior. The maximum water uptake (Msat) increased with chitosan addition, which can be attributed to stronger water–filler interaction. This was correlated to higher diffusion (D), solubility (S) and permeability (P) coefficients, which suggested the acceleration in diffusion rate and better water permeation through the biocomposites. In addition, the tensile results of dry samples showed enhancement in tensile strength and tensile modulus by 2% and 14%, respectively, relative to neat PLA through the incorporation of 2.5 php of chitosan loading. However, the water-immersed biocomposites demonstrated deterioration in all tensile properties (tensile strength, tensile modulus, and elongation-at-break values) which signified hydrolytic polymer degradation. This was confirmed by the FESEM micrographs of the fractured surfaces which exhibited filler pulled-out phenomenon and cavity formation after 50 days of water immersion.

This study aimed to develop novel Polylactic acid/ Halloysite (PLA/ HNTs) films which showed better properties when they were used for food packaging. They also displayed better mechanical, barrier, morphological and structural properties when the researchers analysed the impact of the electron beam irradiation on the nanomaterials. They prepared PLA-based nanocomposites containing 5 % w/w of HNTs using the solution casting process. These nanocomposites were further exposed to different ebeam doses (i.e., 0, 20, 40 and 60 kGy). The researchers assessed the effect of the electron beam irradiation on the various properties of the PLA. All the composites showed a homogenous dispersion and distribution of the HNTs in this PLA matrix. Results indicated that the nanocomposites showed better barrier properties in comparison to the neat PLA. Furthermore, the ebeam irradiation could increase the glass-transition temperature and lead to the development of more crosslinks, which increased the degradation temperature and hydrophilicity of the nanocomposites. In this study, the researchers showed that the PLA/HNTs films were effective materials that could be used for the electron beam processing of the pre-packed foods. The best effect was noted for the 20 kGy dosage which was used in the study.

Polylactic acid (PLA) has recently given a huge attention because of its mechanical properties and good physical like good biodegradability and processability, high tensile modulus and strength. In the current research, the researchers utilized sesame oil (SO) and low molecular weight polyethylene glycol (PEG) as hydrophobic and hydrophilic plasticizers, towards improvise the ductility and toughness of PLA. The researchers synthesized nanocomposites by solution casting of the neat PLA/HNTs and PLA blends with weight ratio of (0,10, 20 and 30 wt%) for PEG and (0, 5 and 10 wt%) for SO. The influence of both plasticizers on chemical, thermal and mechanical properties of the nanocomposites were investigated. Characterization of the systems was achieved by mechanical testing and thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR). The FTIR analyses confirmed the existing of hydrogen bonding between PLA and both PEG and SO. significant improvement was shown by the plasticized nanocomposites in elongation at break with the adding of PEG and SO, meanwhile, the plasticized films’ strength were decreased. For the thermal analyses, all the films exhibited lower thermal stability compared to PLA/HNTs film.

Additive manufacturing (AM) encompasses many forms of technologies and materials as 3D printing is being used in almost all industries. The variety of materials used includes but is not limited to plastics, ceramics, resins, metals, sand, textiles, biomaterials, glass, and food. Currently, in 3D printing technology, the printing mode of direct writing forming is widely applied. The raw material used is ceramic powder, and the direct writing forming of the ceramic could be applied to various fields of materials, chemistry, chemical engineering, and the like. This work is aimed at printing the nanopowder of nonsegregated waste into conventional components. The work is related to a system for converting nonsegregated waste material into the synthesized dough, comprising of a chamber, an ultraviolet (UV) disinfectant unit, a shedder, and a storage unit. The nonsegregated waste material is stored inside the chamber which dispenses the nonsegregated waste material into the UV disinfectant unit; said UV disinfectant unit removes the harmful germs and water content in the nonsegregated waste material to form solid waste. The disinfected solid waste enters the shedder which powders the solid waste. The powdered solid waste is stored in the storage unit. The powdered solid waste is mixed with components in a mixer to form a synthesized dough. The synthesized dough as the printable source is sent to a 3D printer which prints desired final component. The hardness value obtained for the printed component is 70 Brinell hardness units.

Polyvinyl alcohol/palm kernel shell powder biocomposites were prepared by using a solution casting method. To enhance the properties, the crosslinking agent glutaraldehyde (GA) was added to the composition. The effect of the crosslinking agent on the biocomposite was studied based on the change in the tensile properties, physical properties, and biodegradability. The optimum GA content was found to be 2 phr because the tensile properties tended to decrease with higher GA contents. The water absorption percentages and water vapour transmissibility decreased until the GA content reached 2 phr and then increased. It was found that the biodegradability of the film decreased when GA was added.

The ring-opening reaction of epoxide units in an epoxidized natural rubber/titania (ENR-50/TiO2) hybrid in the presence of acetic acid was studied using NMR techniques as well as FTIR spectroscopy. The thermal characteristics of the hybrid were evaluated using TG/DTG and DSC analyses. 1H NMR results suggest that 86.51% of the epoxide rings had opened in the hybrid, and the 13C NMR results revealed new peaks from the hybrid at δ 22.3, 34.8 and 72.2 ppm. 2D NMR (HMQC, HMBC and COSY) techniques further confirmed these assignments. FTIR spectra showed a characteristic Ti-O-C peak at 1028 cm−1. The TG/DTG results showed four decomposition steps at 30-159, 229-325, 325-466 and 664-825 °C due to the presence of Ti moieties along with the mixture of polymer chains i.e., the ring-opened and intact epoxides of ENR-50, which also led to an increase in the Tg value of the hybrid (27.8 °C) compared with purified ENR-50 (-17.7 °C).

The ring opening reaction of epoxidized natural rubber (ENR-50) in the presence of potassium hydroxide/isopropanol solution was studied using NMR, and it's thermal characteristic was investigated using TG/DTG and DSC. 1H-NMR showed that 16.9% of epoxide units was ring-opened in treated ENR-50, which was also supported by quantitative FTIR spectroscopy. 13C-NMR proved the location of alkyl group (isopropyl) in the polymer chain of treated ENR-50. The attachment location of isopropyl occurred at both most (↑) and least (↓) hindered carbons of the epoxide. 2D-NMR was used to identify and scrutinize the triad assignment of treated ENR-50. The TG/DTG results presented three decomposition steps at 190-331, 331-521 and 521–706 °C due to the existence of mixtures of polymer chains i.e. ring-opened and intact epoxide of ENR-50, which also led to increase in Tg of treated ENR-50 at 13.2 °C compared with purified ENR-50 at −17.7 °C.

The positive attributes of excellent biocompatibility and biodegradability of biocomposites with the addition of versatile nanocellulose from agriculture wastes have provided plenty opportunities for further development of functional biocomposite in various fields. Therefore, solvent casting was selected as a reinforcement method in order to produce biocomposite comprise of nanocrystalline cellulose and PLA polymer. Modification of nanocrystalline cellulose through acetylation reaction was conducted upon reinforcement to reduce its surface polarity and hidrophilicity. Biocomposite films prepared at various unmodified (uNC) and acetylated nanocrytalline cellulose (aNC) loading were exposed to morphological (FESEM), tensile test and thermal analysis (TGA). Reinforcement of aNC shows a better dispersion in PLA polymer due to the decreasing of surface polarity, thus increasing inter-facial interaction between both materials. This is proven by greater performance of biocomposite films in tensile strength, Young�s modulus and thermal stability of aNC reinforced PLA as compared to uNC reinforced PLA. Overall, it can be concluded that these research findings can widen the scope of biocomposites research area and have significant implications for the commercial application of biomass products.

Rice husk ash which mostly made up of silica is valuable material for use in industrial applications including production of sodium silicate. Different methods to extract SiO2 from rice husk ash was conducted and the best method was used to prepare poly ferric silicate sulfate coagulant. The prepared coagulant was characterized by using FTIR and SEM. In the coagulation-flocculation process, poly ferric silicate sulfate prepared shows better coagulation performance compared to commercialized polyacrylamide in terms of turbidity removal at three levels of turbidity.