Effect of Vinyl-Terminated Silicone Oil Chain Length and Reinforcing Agent on the Properties of Silicone Rubber

To solve the problems of low strength and high viscosity of room temperature vulcanized liquid silicone rubber, a series of terminated vinyl silicone oil were designed and synthesized, and low viscosity and high strength silicone rubber were prepared by the mechanical reinforcing agent. the results show that the molecular structure of the vinyl-terminated silicone oil has a significant effect on the mechanical properties and viscosity of the silicone rubber, and the best performance is found when the content of vinyl-terminated silicone oil is 0.16%. The low viscosity and high strength silicone rubber prepared from it was reinforced by vinyl MQ resin and fumed silica, which had a significant effect on improving the performance. Its tensile strength increased to 5.03 MPa, elongation at break to 338.90%, and tear strength to 7.15 kN/m compared to conventional silicone rubber, while the hardness increased to 43°. The viscosity is 34.9 Pa•s. The compression modulus is 7.48 MPa.

State-of-the-art review of fabrication, application, and mechanical properties of functionally graded porous nanocomposite materials

Functionally graded porous (FGP) nanocomposites are the most promising materials among the manufacturing and materials sector due to their adjustable physical, mechanical, and operational properties for distinctive engineering applications for maximized efficiency. Therefore, investigating the underlying physical and materialistic phenomena of such materials is vital. This research was conducted to analyze the preparation, fabrication, applications, and elastic properties of functionally graded materials (FGMs). The research investigated for both porous and nonporous synthesis, preparation, and manufacturing methods for ceramics, metallic, and polymeric nanocomposites in the first section, which is followed by deep research of the development of elastic properties of the above-mentioned materials. Main nano-reinforcing agents used in FGMs to improve elastic properties were found to be graphene platelets, carbon nanotubes, and carbon nanofibers. In addition, research studied the impact of nano-reinforcing agent on the elastic properties of the FGMs. Shape, size, composition, and distribution of nano-reinforcing agents were analyzed and classified. Furthermore, the research concentrated on modeling of FGP nanocomposites. Extensive mathematical, numerical, and computational modeling were analyzed and classified for different engineering analysis types including buckling, thermal, vibrational, thermoelasticity, static, and dynamic bending. Finally, manufacturing and design methods regarding different materials were summarized. The most common results found in this study are that the addition of reinforcement units to any type of porous and nonporous nanocomposites significantly increases materialistic and material properties. To extend, compressive and tensile stresses, buckling, vibrational, elastic, acoustical, energy absorption, and stress distribution endurance are considerably enhanced when reinforcing is applied to porous and nonporous nanocomposite assemblies. Ultimately, the review concluded that the parameters such as shape, size, composition, and distribution of the reinforcing units are vital in terms of determining the final mechanical and materialistic properties of nanocomposites.

Developing Edible Starch Film Used for Packaging Seasonings in Instant Noodles

Edible starch-based film was developed for packaging seasoning applied in instant noodles. The edible film can quickly dissolve into hot water so that the seasoning bag can mix in the soup of instant noodles during preparation. To meet the specific requirements of the packaging, such as reasonable high tensile properties, ductility under arid conditions, and low gas permeability, hydroxypropyl cornstarch with various edible additives from food-grade ingredients were applied to enhance the functionality of starch film. In this work, xylose was used as a plasticizer, cellulose crystals were used as a reinforcing agent, and laver was used to decrease gas permeability. The microstructures, interface, and compatibility of various components and film performance were investigated using an optical microscope under polarized light, scanning electron microscope, gas permeability, and tensile testing. The relationship was established between processing methodologies, microstructures, and performances. The results showed that the developed starch-based film have a modulus of 960 MPa, tensile strength of 36 Mpa with 14% elongation, and water vapor permeability less than 5.8 g/m2.h under 20% RH condition at room temperature (25 °C), which meets the general requirements of the flavor bag packaging used in instant noodles.

Effect of Rice Flour Types on the Properties of Nonwoven Pineapple Leaf Fiber and Thermoplastic Rice Starch Composites

Thermoplastic starches and a nonwoven pineapple leaf sheet (NPALF) were prepared. Two types of flours were used to prepare thermoplastic starches (TPSs) which were Rice flour thermoplastic starch (RTPS) and Glutinous rice flour thermoplastic starch (GTPS). Two layers of thermoplastic starches and NPALF layer were sandwiched and pressed by a hot pressing machine at 150°C with 1500 psi for 15 min. All composites were investigated their densities and tensile properties. The density of all composite types had a lower density than each neat TPSs and types of rice flours did not affect their densities. The tensile property results confirmed NPALF could be used as a reinforcing agent both in GTPS and RTPS composites but their tensile improvement effectiveness in both systems are different. NPALF composite with RTPS did not affect the tensile strength but provided a slight improvement in modulus. Remarkably, NPALF composite using GTPS explored the great improvement performance both in strength and modulus which were increased up to 174% and 308% comparing with neat GTPS. SEM micrograph evidence clearly showed good wetting between GTPS and the reinforcement layer in the composite. This is resulting in the NPALF-GTPS composite showed a strong improvement in tensile properties.

Contribution of Harman and Norharman to the Reinforcing Efficacy of Aqueous Tobacco Smoke Extract Self-Administered by Rats

<p>Background: Animal models of drug abuse treat nicotine as the primary reinforcing agent that promotes tobacco addiction. However, rodents demonstrate poor self-administration of nicotine despite evidence of tobacco's high abuse potential in humans. This discrepancy has been attributed to other constituents of tobacco smoke that facilitate the development of nicotine dependence. Objectives: This study aimed to determine whether rats would self-administer intravenous an aqueous tobacco smoke extract (TPM) to find evidence if it was more reinforcing than nicotine alone. The study also evaluated the role of tobacco smoke constituent’s harman and norharman in any differences observed. Methods: Firstly, male Sprague-Dawley rats (n=29) were assigned to treatment groups: nicotine (30.0μg/kg/infusion), TPM (containing 30.0μg/kg/infusion nicotine) or saline vehicle. Ability for each treatment to support intravenous self-administration was assessed using spontaneous acquisition of responding on gradually increasing fixed ratio schedules (FR1, FR2, FR5). Subsequent progressive ratio (PR) testing was employed to determine reinforcing efficacy of each treatment. Then a second group of rats (N = 56) were assigned to treatment groups: nicotine alone (30.0 or 75.0μg/kg/infusion) or nicotine combined with norharman (0, 0.4, 2.5 or 6.25μg/kg/infusion) and harman (0.0, 1.6 or 10.0μg/kg, IP), and tested using a similar protocol. Results: Animals readily acquired self-administration responding for TPM and produced higher PR breakpoints (BP) than rats treated with nicotine alone or vehicle. Rats trained to respond for a larger dose of nicotine demonstrated significantly greater response rates than those receiving the lower dose of nicotine. Finally, the addition of harman and norharman to nicotine significantly reduced BP at the lower unit dose of nicotine tested. Conclusions: These findings support the hypothesis that TPM is more reinforcing than nicotine alone. However, the increased reinforcing efficacy of TPM cannot be attributed to the actions of harman and norharman. The potential role of serotonin inhibition in tobacco reward processes is discussed.</p>

Contribution of Harman and Norharman to the Reinforcing Efficacy of Aqueous Tobacco Smoke Extract Self-Administered by Rats

<p>Background: Animal models of drug abuse treat nicotine as the primary reinforcing agent that promotes tobacco addiction. However, rodents demonstrate poor self-administration of nicotine despite evidence of tobacco's high abuse potential in humans. This discrepancy has been attributed to other constituents of tobacco smoke that facilitate the development of nicotine dependence. Objectives: This study aimed to determine whether rats would self-administer intravenous an aqueous tobacco smoke extract (TPM) to find evidence if it was more reinforcing than nicotine alone. The study also evaluated the role of tobacco smoke constituent’s harman and norharman in any differences observed. Methods: Firstly, male Sprague-Dawley rats (n=29) were assigned to treatment groups: nicotine (30.0μg/kg/infusion), TPM (containing 30.0μg/kg/infusion nicotine) or saline vehicle. Ability for each treatment to support intravenous self-administration was assessed using spontaneous acquisition of responding on gradually increasing fixed ratio schedules (FR1, FR2, FR5). Subsequent progressive ratio (PR) testing was employed to determine reinforcing efficacy of each treatment. Then a second group of rats (N = 56) were assigned to treatment groups: nicotine alone (30.0 or 75.0μg/kg/infusion) or nicotine combined with norharman (0, 0.4, 2.5 or 6.25μg/kg/infusion) and harman (0.0, 1.6 or 10.0μg/kg, IP), and tested using a similar protocol. Results: Animals readily acquired self-administration responding for TPM and produced higher PR breakpoints (BP) than rats treated with nicotine alone or vehicle. Rats trained to respond for a larger dose of nicotine demonstrated significantly greater response rates than those receiving the lower dose of nicotine. Finally, the addition of harman and norharman to nicotine significantly reduced BP at the lower unit dose of nicotine tested. Conclusions: These findings support the hypothesis that TPM is more reinforcing than nicotine alone. However, the increased reinforcing efficacy of TPM cannot be attributed to the actions of harman and norharman. The potential role of serotonin inhibition in tobacco reward processes is discussed.</p>

Evaluation of Novel Compatibility Strategies for Improving the Performance of Recycled Low-Density Polyethylene Based Biocomposites

The interfacial compatibility of the natural filler and synthetic polymer is the key performance characteristic of biocomposites. The fillers are chemically modified, or coupling agents and compatibilisers are used to ensure optimal filler-polymer compatibility. Hence, we have investigated the effect of compatibilisation strategies of olive pits (OP) flour content (10, 20, 30, and 40%wt.) filled with recycled low-density polyethylene (rLDPE) on the chemical, physical, mechanical, and thermal behaviour of the developed biocomposites. In this study, we aim to investigate the filler-polymer compatibility in biocomposites by employing novel strategies for the functionalisation of OP filler and/or rLDPE matrix. Specifically, four cases are considered: untreated OP filled rLDPE (Case 1), treated OP filled rLDPE (Case 2), treated OP filled functionalised rLDPE (Case 3), and treated and functionalised OP filled functionalised rLDPE (Case 4). In general, the evaluation of the performance of biocomposites facilitated the application of OP industrial waste as an eco-friendly reinforcing agent for rLDPE-based biocomposites. Furthermore, surface treatment and compatibilisation improved the properties of the developed biocomposites over untreated filler or uncoupled biocomposites. Besides that, the compatibilisers used aided in reducing water uptake and improving thermal behaviour, which contributed to the stability of the manufactured biocomposites.

Fabrication and Characterization of Composite Materials Using Multiple Waste Materials (Leather & Jute Fabrics) and Unsaturated Polyester Resin

Now a days environment is getting polluted due to different types of manmade reasons than ever for extreme use of synthetic materials. Various kinds of waste materials from numerous industries are also enhancing this. So, Utilization of waste materials and reduction of synthetic materials will definitely subside the environmental pollution. In this research, waste jute fabric and leather waste (cow hides) were used as reinforcing agent and unsaturated polyester resin (UPR) as matrix to prepare environmental friendly composite materials. Hand-lay up method was conducted to fabricate composite materials. Different percentages of waste leather and used jute fabrics were used with the UPR. Improved mechanical properties, tensile strength (TS), tensile modulus (TM), and percentage elongation at break (EB) were observed with the certain percentage of waste materials. Composites were also characterised by the scanning electron microscope (SEM) and fourier transform infrared (FTIR).

Sustainable Chitosan-Dialdehyde Cellulose Nanocrystal Film

In this study, we incorporated 2,3-dialdehyde nanocrystalline cellulose (DANC) into chitosan as a reinforcing agent and manufactured biodegradable films with enhanced gas barrier properties. DANC generated via periodate oxidation of cellulose nanocrystal (CNC) was blended at various concentrations with chitosan, and bionanocomposite films were prepared via casting and characterized systematically. The results showed that DANC developed Schiff based bond with chitosan that improved its properties significantly. The addition of DANC dramatically improved the gas barrier performance of the composite film, with water vapor permeability (WVP) value decreasing from 62.94 g·mm·m−2·atm−1·day−1 to 27.97 g·mm·m−2·atm−1·day−1 and oxygen permeability (OP) value decreasing from 0.14 cm3·mm·m−2·day−1·atm−1 to 0.026 cm3·mm·m−2·day−1·atm−1. Meanwhile, the maximum decomposition temperature (Tdmax) of the film increased from 286 °C to 354 °C, and the tensile strength of the film was increased from 23.60 MPa to 41.12 MPa when incorporating 25 wt.% of DANC. In addition, the chitosan/DANC (75/25, wt/wt) films exhibited superior thermal stability, gas barrier, and mechanical strength compared to the chitosan/CNC (75/25, wt/wt) film. These results confirm that the DANC and chitosan induced films with improved gas barrier, mechanical, and thermal properties for possible use in film packaging.

Effect of Chemically Treated Kenaf Fibre on Mechanical and Thermal Properties of PLA Composites Prepared through Fused Deposition Modeling (FDM)

Natural fibre as a reinforcing agent has been widely used in many industries in this era. However, the reinforcing agent devotes a better strength when embedded with a polymer matrix. Nevertheless, the characteristic of natural fibre and polymer matrix are in contrast, as natural fibre is hydrophilic, while polymer is hydrophobic in nature. Natural fibre is highly hydrophilic due to the presence of a hydroxyl group (-OH), while polymer matrix has an inherent hydrophobic characteristic which repels water. This issue has been fixed by modifying the natural fibre’s surface using a chemical treatment combining an alkaline treatment and a silane coupling agent. This modifying process of natural fibre might reduce the attraction of water and moisture content and increase natural fibre surface roughness, which improves the interfacial bonding between these two phases. In this paper, the effect of alkaline and silane treatment has been proven by performing the mechanical test, Scanning Electron Micrograph (SEM), and Fourier Transform Infrared spectrometry (FTIR) to observe the surface structure. The chemical compositions and thermal properties of the composites have been obtained by performing Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) tests. 1.0% silane treatment displayed better strength performance as compared to other composites, which was proven by performing Scanning Electron Micrograph (SEM). The assumption is that by enduring chemical treatment, kenaf fibre composites could develop high performance in industry applications.