Effect on thermal properties of nanocellulose fibre (NCF) reinforced biodegradable polyhydroxylalkanoates (PHA) composite

Currently, biodegradable materials like polyhydroxyalkanoates (PHA) and polylactic acid (PLA) are receiving huge attention from the both scientific and industrial sectors. However, since PHA has poor thermal properties, there is a shortfall in the exploration of PHA ability with filler. Therefore, this research aim is to investigate the thermal effect of nanocellulose fiber (NCF) fillers with PHA polymer. The first solution of PHA composite is prepared by dissolving 1g of PHA in 40mL of dichloromethane at 30°C for 10 minutes. The PHA-NCF composite solution is prepared by adding 1wt%, 2wt%, 3wt%, and 4wt% of NCF dissolved in 40 mL of dichloromethane into the PHA solution. The mixture solution is agitated at 45°C with a magnetic stirrer for 10 minutes. The mixture is poured into a petri dish. The prepared films were characterized by Differential Scanning Calorimeter (DSC), Fourier Transforms Infrared Spectroscopy, (FTIR), and Thermogravimetric Analysis (TGA). The FTIR analysis shows that all PHA/NCF composite samples contain similar functional groups when compared with the pure PHA. No significant changes on the thermal properties of the PHA composite was observed with the addition of NCF fillers. However, comparison within the PHA/NCF samples shows that the PHA with 2% of NCF has a higher melting temperature and requires the highest enthalpy of melting. Hence, the addition of 2% of NCF is selected to be the optimum amount of NCF filler addition to the PHA composite

Biodegradability effects on the PHA/NFC nanocomposite

Plastic has been harmful to the environment and lead to endless pollution due to years of disposal. However, its usage is undeniable hence an alternative to using biodegradable plastic replacing regular everyday plastic is highly recommended. Polyhydroxyalkanoates (PHA) have all characteristics needed as a biodegradable plastic however, it exhibits brittleness, poor thermos-mechanical properties, and low heat distortion temperature. Therefore, the objective was to investigate the effect of nanofibril cellulose (NFC) addition on the biodegradability properties of PHA composite. The biodegradation properties were investigated using a soil burial test. The samples were incubated for 7, 14, 21, and 28 days under control conditions, and weight loss for both characterizations was recorded to identify the effectiveness of NFC in the PHA composite. For the result, the weight of samples was decreased with an increase in incubation time, while its percentage of weight loss was increased as the hydrophilicity of NFC caused the sample to degrade at a higher rate. Although PHA/NFC samples were having a lag time at the earliest stage, it is then degraded better than pure PHA after 21 days. In conclusion, the addition of NFC has greatly improved PHA properties where PHA/NFC 8% is the most sufficient nanocomposite to turn PHA into promising biodegradable plastics and safe for daily usag

Thermal and morphological properties of polyhydroxyalkanoate / nanosilver composite

Conventional plastic can lead to endless pollution as it took millions of years to be disposed of, hence an alternative to using biodegradable plastic replacing regular everyday plastic has highly participated. Polyhydroxyalkanoates (PHA) have the characteristics of a biodegradable plastic however, it exhibits low heat distortion temperature. The objective of this research is to investigate the effect of nanosilver additions on the thermal properties of the PHA composite and its morphology behavior. Initially,4 wt/v of PHA was dissolved into 30mL dichloromethane at room temperature. After that, the nanosilver particle was added with 10mL dichloromethane and it was ultrasonicated at 10 minutes. Ultrasonicated nanosilver in dichloromethane mixture was mixed with PHA in dichloromethane for 20 minutes using a magnetic stirrer. Then, thin polymeric films with a thickness of 10 µm were obtained by the solution casting method. The obtained films were then carefully dried at room temperature for 24 hours. These steps were repeated with the addition of 0.25 wt% and 0.5wt% nanosilver suspension in dichloromethane to PHA solution. The thermal properties and morphology analysis of PHA/nanosilver composite will be investigated using thermal gravimetric analysis(TGA) and field emission scanning electron microscopy (FESEM). Based on thermal properties, PHA/0.5wt% nanosilver has shown a lower onset temperature compared to the pure PHA. This indicates that PHA/0.5wt% nanosilver has a slower degradation rate and higher thermal stability. In conclusion, nanosilver has greatly improved PHA properties into promising biodegradable plastics

Modelling of single and binary adsorptions of heavy metals onto activated carbon - equilibrium studies

A series of batch laboratory studies were conducted to investigate the suitability of activated carbon SA2 for the removal of cadmium ions and zinc ions from their aqueous solutions. The single component equilibrium data were analyzed using the Langmuir and Freundlich isotherms. Overall, the Langmuir isotherm showed a better fitting for all adsorptions under investigation in terms of correlation coefficient and error analysis (SSE only 18.2 for Cd2+ and 47.95 for Zn2+). As the binary adsorption is competitive, extended Langmuir models could not predict the binary component isotherm well. The modified extended Langmuir models were used to fit the binary system equilibrium data. The binary isotherm data could be described reasonably well by the modified extended Langmuir model, as indicated in the error analysis

Segregated nanofiller: Recent development in polymer-based composites and its applications

An ordinary conductive polymer composite (CPCs) generally requires high amount of conductive filler at insulator to conductor transition, need complex processing and display poor mechanical properties. High value of the conductivity with outstanding mechanical properties can be achieved by segregated conductive polymer composite (s-CPCs) which somehow is still challenging and required more extensive research. To understand more on the formation and properties of the s-CPCs, this review briefly discussed on general information on the s-CPCs, the morphology in term of filler dispersion, the factors affecting the properties (e.g. types of polymer host, types of filler, concentration of the conductive filler), and the potential applications of s-CPC

Synthesis of superabsorbent carbonaceous kenaf fibre filled polymer via inverse suspension polymerisation

This paper studies the synthesis of superabsorbent carbonaceous kenaf fibre filled polymer using inverse suspension polymerisation method. The kenaf fibre was prepared using the hydrothermal carbonisation process. Inverse suspension polymerisation process involved two different solution mixtures; a continuous phase containing cyclohexane, span-80, and kenaf fibre filler and a dispersed phase containing partially neutralised acrylic acid, acrylamide, initiator APS, and crosslinker NN-Methylenebisacrylamide. Kenaf fibre filler addition was varied with different weight percentages (0.01- 0.05 wt%). Water absorption testing using the teabag method showed sample containing 0.04 wt% carbon filler had the highest and optimal percentage of water absorbency, 55.27 g/g while the sample containing 0.01 wt% carbon filler displayed the lowest percentage of water absorbency, 45.27 g/g. All SPC samples showed a higher rate of water absorbency compared to SAP sample which had 40.61 g/g of average water absorbency. The samples were characterised by FTIR, FESEM - EDX, Mastersizer. All synthesised samples produced were in spherical beads form. It can be concluded that kenaf fibre affects the enhancement of superabsorbent polymer performance

Waste materials as the potential phase change material substitute in thermal energy storage system: A review

Phase change material (PCM) has been recognized as one of the important element in the energy storage and conservation management. PCM and its combination has been widely used in many applications and significant number of literatures has been published to highlight the potential use of PCM as thermal energy storage (TES) material. However, although the information is quantitatively enormous and the application of waste has becoming a trending subject nowadays, documented researches on PCM material derived from waste material are still very scarce. Therefore, in this paper, in-depth reviews on the implementation of potential waste materials in PCM considering its purposes in improving the TES performance, economic values and environment were reviewed and elaborated. Overall, this review shows potential utilization of waste materials as a new material substitute to produce an efficient, cost-effective and environmentally friendly PCM in the future TES system

Silver nitrate concentration on silver nanoparticles formation attached on cellulose nanocrystal matrix

Cellulose nanocrystals (CNCs) with silver nanoparticle composites are used in various applications, ranging from packaging to biomedical. Therefore, the optimum performance of this hybrid nanomaterial can be achieved by controlling agglomeration in the silver nanoparticle synthesis. The agglomeration behaviour can be monitored by integrating CNCs as polymer matrix during the synthesis. This work aimed to investigate the effect of silver nanoparticles (AgNPs) synthesised from different silver precursor concentrations and loaded on the surface of CNCs. The cellulose nanocrystal was isolated from an oil palm empty fruit bunch (EFB). The AgNPs were synthesised by using the reduction technique of silver nitrate at 0.1 M and 0.5 M concentrations and with the aid of glucose solution. The AgNPs_CNC nanosuspension was analysed by using UV–Vis spectroscopy, FTIR, DSC, and FESEM/EDX. The spectroscopy data from UV–Vis indicated a strong absorption peak at 385 nm due to the formation of the nanoparticles in AgNPs_CNC_0.5 nanosuspension. Meanwhile, the morphological result showed that the AgNPs formed were spherical in shape (57.8 nm) with strong existence of silver, carbon, and oxygen. Therefore, the AgNPs_CNC nanosuspension was successfully synthesised by using 0.5 M silver nitrate with uniform and well-distributed nanoparticles

The utilization of phase change material (pcm) composite derived from fatty acids and waste materials as thermal energy storage (tes) medium

Implementation of organic materials in the thermal energy storage (TES) systems has been one of the most attractive candidates in improving the heat and energy storages as well as preserving the environment. Organic PCM such as fatty acid has been discovered to have high heat capacity, good chemical stability, low or non- supercooling, non-corrosive, small volume change, low vapor pressure and low cost. However, problem associated with low thermal conductivity has become one of the major drawbacks of PCM derived from fatty acids. Therefore, in-depth researches have been conducted and PCM composite containing fillers such as nanowires, metallic, and carbon additives has been formulated to investigate the potential of these materials to improve the performance of conventional organic PCM during heating and cooling application in solar system. As they observed the thermal properties between the formulated PCM composite, PCM with carbon additives has shown the obvious advantages but the other PCM fillers properties were excellent too. Despite their good performance, in terms of economic value, it is quite pricy. From the study, the performance of PCM composite using nanowires and metallic particles was poorer compared to the carbon additives (i.e. expanded graphite, graphene oxide, and activated carbon) during heating and cooling application in solar system. Despite that, the performance is still excellent for the thermal storage and thermal conductivity of all elements but, in terms of economic value, it is quite pricy. Therefore, several solutions have been identified to enhance the thermal conductivity of the conventional PCM whilst producing cheaper PCM composite

Synthesis and characterisation of microcrystalline cellulose-g-poly (Acrylamide) superporous absorbent composite using graft polymerisation methods

Superabsorbent polymer was synthesised by using graft polymerisation method incorporated with micro crystalline cellulose (MCC) as a filler and sodium bicarbonate (NaHCO3) as the foaming agent. The addition of organic filler and porosity generator produced a highly porous biodegradable superabsorbent polymer composite (HP-PAM-g-MCC), which improved the characteristics of the acquired products, in comparison with the conventional SAP. Determination of water absorbency was tested by using the tea bag method after immersing in distilled water. The effects on amount of MCC and sodium bicarbonate addition towards water absorbency were studied to determine the optimum condition of PAM-g-MCC SAPs composite. The maximum water absorbency of PAM-g-MCC composite was achieved at 1.0 wt% of MCC and 1 wt% NaHCO3, resulting in 74.01 g/g and 93.96 g/g of water absorbency, respectively. The Fourier transform infrared (FTIR) and scanning electron microscope (SEM) analyses data revealed the presence of chemical bonding and morphological characteristics corresponding to the water absorption capacity of HP-PAM-g-MCC