Porous polysaccharides have recently attracted attention due to their porosity, abundance, and excellent properties such as sustainability and biocompatibility, thereby resulting in their numerous applications. Recent years have seen a rise in the number of studies on the utilization of polysaccharides such as cellulose, chitosan, chitin, and starch as aerogels due to their unique performance for the fabrication of porous structures. The present review explores recent progress in porous polysaccharides, particularly cellulose and chitosan, including their synthesis, application, and future outlook. Since the synthetic process is an important aspect of aerogel formation, particularly during the drying step, the process is reviewed in some detail, and a comparison is drawn between the supercritical CO2 and freeze drying processes in order to understand the aerogel formation of porous polysaccharides. Finally, the current applications of polysaccharide aerogels in drug delivery, wastewater, wound dressing, and air filtration are explored, and the limitations and outlook of the porous aerogels are discussed with respect to their future commercialization.
The environmental problem due to plastic waste had become serious because it could not be recycled neither be degraded naturally by microbe in land. Thus, in the present study, a bioplastic was produced based on cassava starch as the matrix and cellulose nanocrystal (CNC) from Mangosteen peel as reinforcing filler. The CNC was added into the bioplastic with varied concentration at 1 g (BP2), 2.5 g (BP3), 5 g (BP4) and without CNC as BP1. The isolation of CNC followed series of steps (delignification, bleaching, hydrolysis and sonication) before added to the matrix. The effect of CNC addition towards mechanical properties was determined using universal testing machine (UTM) and analyzed using Fourier transform infrared (FTIR) spectroscopy. Results showed that the FTIR analysis confirmed an absorption pattern of cellulose in the starch/CNC bioplastic matrix whereas the effect in tensile strength, tensile modulus and elongation at break were compared to the pure bioplastic without CNC. The highest tensile strength peaked at 1.93 MPa while Young’s modulus at 26.82 GPa was observed for BP1. On the contrary, the addition of CNC fillers to the bioplastics increased the elongation at break and the density while the elongation at break reached the lowest percentage is 13.93% and the lowest density value is 952.5 kg/m3. Based on overall observation, this study proved that the addition of CNC on the other hand the mechanical properties showed the different result.
We
report that conjugated polymer nanoparticles (CPNs) coated with
polyethylene glycols (PEGs) exhibit photothermal and photodynamic
capabilities according to molecular ordering in their assembly structures.
CPN-PEGs were made using three different methods: a dispersion process
of phase-separated film assemblies of a conjugated polymer and a phospholipid-conjugated
PEG (CPN-I), a dispersion process of a conjugated polymer and a phospholipid
followed by surface conjugation with PEGs (CPN-II), and a miniemulsification
of the conjugated polymer and the phospholipid-conjugated PEG. Our
findings revealed that the ordered molecular assembly structures in
CPN-I and CPN-II increased intermolecular interactions and decreased
the optical band gap, promoting nonradiative exciton relaxation via
the energy-gap law’s internal conversion mechanism and rationalizing
CPN-I’s shorter singlet exciton lifetime (13 ps). Meanwhile,
CPN-III with a disordered structure generated more singlet oxygen
than CPN-I and CPN-II, indicating increased triplet exciton generation
upon the polaron recombination. Our findings present that the photothermal
and photodynamic properties of CPNs are obviously dependent on the
assembly structure order and that CPNs with an ordered assembly of
conjugated backbones have a stronger photothermal effect, whereas
those with a disordered structure have a better photodynamic effect.
Oil pollution has become a water pollution problem in the world. An eco-friendly adsorbent need to be produced to resolve this problem. This study focuses on removing oil waste using Chempedak Stone (CS) powder as a natural adsorbent. The purpose of the study is to observe the effects of adsorbent dosage and the effects of several type of water sources on adsorbing different types of oils (vegetable oil, lubricant oil and diesel oil). Different adsorbent dosage (treated and untreated) of 0.2g, 0.4g, 0.6g, 0.8g and 1.0g was examined in different types of water which are tap water, sea water and lake water. The treated adsorbent was introduced to 0.5M NaOH and 0.5M nitric acid (HNO3). The CS was collected from a local market and went through several processes to become a powder such as rinsing, drying, crushing and sieving. The results show that the increasing adsorbent dosage decreased the percentage of oil removal. It was proven that the effectiveness of treated and untreated adsorbent depended on the type of oil and the type of water. The highest percentage of oil removal was found using untreated CS powder on vegetable while treated CS powder was effective for adsorbing lubricant oil at the dosage of 0.2g. The results thus showed that untreated CS powder has the most effective adsorbent to adsorb various types of oils on various types of water compared to treated CS powder.
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