Investigation on the influence of waste-based fillers on the mechanical and thermal characteristics of rigid polyurethane foams

An investigation was conducted to analyze the impact of incorporating coal powder particles at different weight ratios (5, 10, 15, 25, and 35) on the mechanical properties and thermal conductivity coefficient of the polyurethane polymer. The thermal conductivity coefficient of the samples was calculated using Holmarc's Lee's Disc apparatus device. The mechanical properties like compressive, tensile, and bending strengths were measured using a universal machine. The results indicated that increasing the coal powder ratio leads to an improvement in the thermal insulation ability due to a decrease in the value of thermal conductivity. Also, the addition of these percentages led to a rise in the values of the mechanical qualities represented by the compressive strength, especially at the ratio of 25 wt. %, with a value equal to 2.79 MPa (MPa). The flexural resistance and tensile strength increase at a ratio of 35 wt. %, with values equal to 20.4 MPa and 2.86 MPa respectively. The results indicate that the addition of coal powder enhances the ability of thermal conductivity at the ratios (5 %, 10) wt. %, with values equal to 0.119 W/m ºC and 0.114 W/m ºC, respectively, by increasing the thermal conductivities of the samples. The aim of this study is, investigate the effect of filler used coal powder waste on the mechanical and thermal properties of PU. The filler materials show the advantages of recycling waste. Filler influences the morphology and strengthens the brittleness. Additionally, the technology of polyurethane materials conforms to the use of coal powder. The overall amount of energy used to produce PU composites is decreased when waste of filler is used to partially replace petrochemical component

Excellent Anti-bacterial Activity of Poly(o-toluidine)-DBSA/ ZnO Nanocomposite

This work presents a study of the biological application (antibacterial activity) of ZnO/poly(o-toluidine) (POT) doped with organic acids dodecylbenzene sulfonate acid (DBSA) nanocomposites synthesized by in-situ polymerization of (o-toluidine) monomer in presence of 5% ZnO. The FTIR spectroscopy confirms the existence of an interaction between POT-DBSA matrix and ZnO particles. Scanning electron microscopy reveals the nanostructure nature of the obtained composite. The antibacterial activity of POT-DBSA/ZnO nanocomposite and POT-DBSA studied by agar well diffusion method, was found to increase with increasing concentration meanwhile POT/DBSA/ZnO exhibits better antibacterial activity compared to POT/DBSA and POT separately. Keywords: Poly(O-toluidine); Organic acid; ZnO; nanocomposite; antibacterial activity. DOI: 10.7176/APTA/81-04 Publication date: December 31st 201

Comparative study of the antioxidant capability of EDTA and Irganox

Oxidative stress makes it difficult to preserve food and negatively affect the applicability of polymeric packaging. It is typically caused by an excess of free radicals, and it is dangerous to human health, resulting in the onset and development of diseases. The antioxidant ability and activity of ethylenediaminetetraacetic acid (EDTA) and Irganox (Irg) as synthetic antioxidant additives were studied. Three different antioxidant mechanisms were considered and compared by calculating bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) values. Two density functional theory (DFT) methods were used, M05-2X and M06-2X with the 6–311++G(2d,2p) basis set in gas phase. Both additives can be used to protect pre-processed food products and polymeric packaging from oxidative stress related material deterioration. By comparing the two studied compounds, it was found that EDTA has a higher antioxidant potential than Irganox. To the best of our knowledge several studies have been carried out to understand the antioxidant potential of various natural and synthetic species, but EDTA and Irganox were not compared and investigated before. These additives can be used to protect pre-processed food products and polymeric packaging and prevent material deterioration caused by oxidative stress

Antioxidant Potential of Santowhite as Synthetic and Ascorbic Acid as Natural Polymer Additives

A wide variety of additives are used to improve specific characteristics of the final polymeric product. Antioxidant additives (AAs) can prevent oxidative stress and thus the damage of polymeric materials. In this work, the antioxidant potential and thus the applicability of Santowhite (SW) as synthetic and ascorbic acid (Asc) as natural AAs were explored by using computational tools. Two density functional theory (DFT) methods, M05-2X and M06-2X, have been applied in combination with the 6-311++G(2d,2p) basis set in gas phase. Three antioxidant mechanisms have been considered: hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) have been computed for each potential hydrogen donor site. The results indicate that the antioxidant potential of Asc is higher than SW. Furthermore, some of the C-H bonds, depending on their position in the structures, are potent radical scavengers, but O-H groups are more prone to donate H-atoms to free radicals. Nonetheless, both additives can be potentially applied to safeguard common polymers and prohibit oxidative stress-induced material deterioration