Thermoplastic starch (TPS) hybrid bio-composite films containing microcrystalline cellulose (C) and nano-bentonite (B) as hybrid fillers were studied to replace the conventional non-degradable plastic in packaging applications. Raw oil palm empty fruit bunch (OPEFB) was subjected to chemical treatment and acid hydrolysis to obtain C filler. B filler was ultra-sonicated for better dispersion in the TPS films to improve the filler–matrix interactions. The morphology and structure of fillers were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). TPS hybrid bio-composite films were produced by the casting method with different ratios of B and C fillers. The best ratio of B/C was determined through the data of the tensile test. FTIR analysis proved the molecular interactions between the TPS and the hybrid fillers due to the presence of polar groups in their structure. XRD analysis confirmed the intercalation of the TPS chains between the B inter-platelets as a result of well-developed interactions between the TPS and hybrid fillers. SEM images suggested that more plastic deformation occurred in the fractured surface of the TPS hybrid bio-composite film due to the higher degree of stretching after being subjected to tensile loading. Overall, the results indicate that incorporating the hybrid B/C fillers could tremendously improve the mechanical properties of the films. The best ratio of B/C in the TPS was found to be 4:1, in which the tensile strength (8.52MPa), Young’s modulus (42.0 MPa), elongation at break (116.4%) and tensile toughness of the film were increased by 92%, 146%, 156% and 338%, respectively. The significantly improved strength, modulus, flexibility and toughness of the film indicate the benefits of using the hybrid fillers, since these features are useful for the development of sustainable flexible packaging film.

Recently, hybrid fillers have been widely used to improve the properties of biopolymers. The synergistic effects of the hybrid fillers can have a positive impact on biopolymers, including thermoplastic corn starch film (TPCS). In this communication, we highlight the effectiveness of hybrid fillers in inhibiting the aging process of TPCS. The TPCS, thermoplastic corn starch composite films (TPCS-C), and hybrid thermoplastic corn starch composite film (TPCS-HC) were stored for 3 months to study the effect of hybrid filler on the starch retrogradation. TPCS-C and TPCS-HC were prepared by casting method with 5 wt% of fillers: nanocellulose (NC) and bentonite (BT). The alteration of the mechanical properties, aging behavior, and crystalline structure of the films were analyzed through the tensile test, Fourier transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and water absorption analysis. The obtained data were correlated to each other to analyze the retrogradation of the TPCS, which is the main factor that contributes to the aging process of the biopolymer. Results signify that incorporating the hybrid filler (NC + BT) in the TPCS/4BT1NC films has effectively prevented retrogradation of the starch molecules after being stored for 3 months. On the contrary, the virgin TPCS film showed the highest degree of retrogradation resulting in a significant decrement in the film’s flexibility. These findings proved the capability of the green hybrid filler in inhibiting the aging of the TPCS.

Thermoplastic starch (TPS) was studied extensively to replace conventional plastic in packaging application. In this study, granule corn starch was first plasticized with water and glycerol to form TPS films and two different fillers were incorporated with TPS to form hybrid biocomposite films (TPSB). Two different fillers: Microcrystalline cellulose (MC) and Nano bentonite (NB) fixed at 1: 4 ratios in various loading (1wt%-6wt%) were incorporated in TPS to study effect of hybrid fillers on the mechanical properties of TPSB films. The effect of different loading of MC/NB on TPSB films was investigated through the structural, morphological and mechanical testing. Fourier Transform Infrared Spectroscopy (FTIR) shows TPS matrix and hybrid fillers are highly compatible due to hydroxyl bonding and verified through the shifting of spectra band. Scanning Electron Microscope (SEM) showed even distribution of fillers in the matrix of TPS. The TPSB films exhibited significant improvement 40% in elongation at break compared to pure TPS films. In this study, 5wt% is best loading of the hybrid fillers to incorporated in TPSB films as it achieved the highest value of tensile strength (8.52MPa), Young’s Modulus (42.0 MPa) and elongation at break (116.3%). Generally, previous studies showed flexibility of TPS composite films reduced with incorporating filler, however in this study, the flexibility TPSB show significant improvement compared to previous studies and exhibit promising potential in dry food packaging application.

This study focuses on investigating the effect of hybrid nanofillers on the hydration characteristics and soil biodegradability of the thermoplastic corn starch (TPCS) hybrid nanofiller biocomposite (TPCS-HB) films. The data were benchmarked with that of the pure TPCS and TPCS single nanofiller biocomposite (TPCS-SB) as control films. The water absorption properties of TPCS, TPCS-SB, and TPCS-HB films were analyzed and fitted with the standard Guggenheim–Anderson–de Boer equation to study the water activity of the films. Besides, the water permeability test, water vapor permeability, and soil biodegradability of the films were also studied and correlated with the films’ surface morphology. The results indicated that the TPCS-HB films possess excellent hydration resistance and comparable biodegradable rate with the TPCS-SB films. The optimal water resistance properties were achieved when the optimal ratio of nanobentonite/nanocellulose (4:1) was incorporated into the TPCS matrix. The outcomes of this study provide an innovative idea and new insights that, by using natural and hybrid nanofillers, the hydrophobicity of the TPCS films could be enhanced. TPCS-HB films show great potential to be developed into a fully green biodegradable TPCS biocomposite film, especially for single-use plastic applications.

Thermal comfort is a part of indoor environmental quality that should be considered to ensure the occupants' well-being. Unconducive buildings not only bring occupants discomfort but also tend to affect health, disrupt the process of teaching and learning, and reduce work productivity. Thus, this study determines the thermal condition of existing workshop buildings used in Technical and Vocational Education and Training (TVET) implementation. ASHRAE Standard 55 (2017) is referred to in the determination of thermal comfort involving objective measurements and subjective measurements. Observation methods of environmental variables such as air temperature, radiant temperature, air velocity, relative humidity is observed. Evaluations of comfort are based on occupant surveys and environmental measurements. A total of 257 people completed a questionnaire distributed at three technical institutions in Kedah, Malaysia. According to the findings, the average thermal sensation vote is 1.85, which leads to 66.5% of respondents feeling discomfort. Meanwhile, the adaptive model analysis showed that the workshop environmental conditions were out of the comfort zone and did not comply with the ASHRAE 55 standard. Hence, the thermal discomfort factors from the occupants' perspective were identified and widely discussed. As a result, the research findings will benefit parties involved in new building construction or existing building renovations to improve indoor air quality.