Shellac as a Multifunctional Additive (MFA) in a Typical Truck Tyre Sidewall Compound
01 Nov 2012-Progress in Rubber Plastics and Recycling Technology (SAGE Publications)-Vol. 28, Iss: 4, pp 173-188
TL;DR: In this article, some unexplored features of naturally occurring Indian shellac present in a typical truck tyre sidewall compound, at low doses with the intention of replacing stearic acid in the formula.
Abstract: This study reports some unexplored features of naturally occurring Indian shellac present in a typical truck tyre sidewall compound, at low doses with the intention of replacing stearic acid in the formula. The chemical characterization of shellac was determined using Fourier transform infrared (FTIR) spectroscopy, along with information from earlier published reports, revealing the presence of different fatty acids, alcohols, esters and quinone-based dyes. The substitution of stearic acid with shellac shows that 50% replacement of the acid with shellac obtained comparable rheometric and physical properties with the control compound. The presence of different components in shellac further helped to improve ageing and reversion resistance. The volatile loss from shellac is much lower compared with commercial stearic acid. Some essential properties for sidewall application such as extrudate shrinkage and die swell behaviour were also found to be suitable when 50% of the commercial stearic acid was replaced with shellac in the formula.
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TL;DR: In this article , three kinds of melamine-formaldehyde (MF) microcapsules, containing transparent shellac, purple shellac and yellow shellac as core curing agents, were synthesized via in situ polymerization, and then were embedded into the water-based acrylic resin coatings.
Abstract: Three kinds of melamine-formaldehyde (MF) microcapsules, containing transparent shellac, purple shellac, and yellow shellac as core curing agents, were synthesized via in situ polymerization, and then were embedded into the water-based acrylic resin coatings according to the concentrations of 0, 3.0%, 6.0%, 9.0%, 12.0%, and 15.0%, respectively, to obtain waterborne films with different microcapsule contents. The color of different shellacs was relevant to the color parameters of the self-healing waterborne film. The content of microcapsules was negatively correlated with the chromatic aberration of the surface of waterborne films. When the content of microcapsules was 0–6.0%, the chromatic aberration of waterborne films was relatively low. The content of microcapsules and the color of the different shellacs would affect the light transmittance of waterborne films. Among all samples, the light transmittance of the waterborne film containing 3.0% transparent shellac microcapsules was the highest. The microcapsules with different colors of shellac in waterborne films had different self-repairing effects. When the content of microcapsules did not exceed 6.0%, the tensile repair rate of the waterborne film containing yellow shellac encapsulated microcapsules was the highest, at 47.19%. The scratch experiment illustrated that the scratch width of the waterborne coating with yellow shellac microcapsules decreased most significantly, and the width change rate was 73.0% after 5 days. The coating containing the 3.0% yellow shellac microcapsule has the best comprehensive performance on optical and self-healing properties. Exploring the influence of shellac resin’s color and the microcapsules’ content on the waterborne film provides technical references for the application of shellac in waterborne coatings and contribute to the further development of the preparation process of self-healing coatings.
4 citations
TL;DR: In this article, a novel selective physical separation technology of waste tires is developed, presented and investigated, based on a new disassembling machine that enables the selective separation of the tread material of any kind of tires apart from their other constituting materials.
Abstract: The annual amount of waste tires is enormous and permanently on the increase. Since their structure resists both physical and chemical degradation, their appropriate processing is an environmentally important subject and it is still a current research topic despite of the already existing technologies e.g. pyrolysis, thermal utilization. In our work, a novel selective physical separation technology of waste tires is developed, presented and investigated. The technology is based on our new disassembling machine that enables the selective separation of the tread material of any kind of tires apart from their other constituting materials. The separation is an automated cutting process and its thermal profile is examined with a thermal imaging camera to determine if the cutting process can be associated with any kind of thermal degradation of the tread material. It is also an aim to detect if a special construction material of high thermal resistance would be needed for the cutting device. The experimental results are analyzed with the help of special software and it is found that the temperature values of the tire and the disassembling device can be classified into four different thermal zones. It is also determined that our novel device can be applied for tire machining; no thermal degradation occurs during the process, and there is no need for special construction material for the novel cutting device.
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TL;DR: In this article, a method to determine chemical composition of natural resin shellac was developed on the basis of reactive pyrolysis−gas chromatography (Py-GC) in the presence of an organic alkali, tetramethylammonium hydroxide ((CH3)4NOH, TMAH).
Abstract: A method to determine chemical composition of natural resin shellac was developed on the basis of reactive pyrolysis−gas chromatography (Py-GC) in the presence of an organic alkali, tetramethylammonium hydroxide ((CH3)4NOH, TMAH). Py-GC using 25% TMAH aqueous solution enabled the highly sensitive determination of terpenic acids, aleuritic acid, several minor fatty acids, and the wax components of shellac as their methyl derivatives on the resulting pyrograms with less than 2.0% relative standard deviations without using any cumbersome pretreatment. The observed average distributions of each resin acid component determined by reactive Py-GC for shellac samples from India and Thailand showed that the average ratios among terpenic acids, aleuritic acid, and the other fatty acids were about 53:34:14 for Indian shellac and 51:35:14 for Thailand shellac, respectively, suggesting a slightly significant difference. However, clearer discrimination of the shellac samples from the two different growing places was at...
60 citations
TL;DR: In this article, the structural studies of shellac molecules have been reviewed and an attempt has been made to review the literature on modification to make it more acceptable to meet the growing demand of the users.
Abstract: The paper attempts to document upto date status of the structural studies of Shellac. Attempt has also been made to review the literature on modification of shellac molecules to make it more acceptable to meet the growing demand of the users.
49 citations
TL;DR: In this article, the antioxidant activity of green tea, black tea, Lippia citriodora, Hypericum androsaemum, and Liam et al. was investigated as a potential source of antioxidants for polypropylene.
Abstract: Several natural matrices were investigated as potential sources of antioxidants to be used as plastic additives. Extracts of four matrices obtained under the same experimental conditions were initially considered: green tea, black tea, Lippia citriodora and Hypericum androsaemum. Both, the antioxidant activity of the extracts and their content in flavanols and quercetin, were compared. The antioxidant activity was determined by DPPH analysis and the phenolic composition by high performance liquid chromatography (HPLC) using ultraviolet (UV) diode array and fluorescence (FL) detectors. Concentration of the flavanols reduced in the same way as their antioxidant activity starting with green tea, through black tea, Hypericum androsaemum, and Lippia citriodora. The performance of polypropylene samples stabilized with green tea extract, or its individual components catechin and epicatechin, was compared with samples stabilized with a mixture of the synthetic antioxidants Irganox 1076 and Irgafos 168. Each sample was extruded and consecutively reextruded up to four times. The melt flow index (MFI) and the oxidation induction time (OIT) of the samples were measured after each step. The obtained results showed the interest of this natural matrix as a potential source of antioxidants for plastics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
46 citations
TL;DR: In this article, Linseed oil is used in the dual roles of the plasticizer and the fatty acid component of the activator in nitrile rubber vulcanizates.
Abstract: Linseed oil is used in the dual roles of the plasticizer and the fatty acid component of the activator in nitrile rubber vulcanizates. The study shows that the substitution can substantially improve the mechanical properties in addition to other advantages such as increased cure rate, reduced leachability and reduced compound cost.
23 citations
TL;DR: Lac is the only known natural resin of animal origin and the secretion of a tiny insect known as Kerriar lacca (formally called Laceifer lacca) grows on some types of trees, mostly abundant in tropical countries, including India.
Abstract: Lac is the only known natural resin of animal origin. It is the secretion of a tiny insect known as Kerriar lacca (formally called Laceifer lacca). The lac-forming tiny insect grows on some types of trees, mostly abundant in tropical countries, including India. The secretion of the lac insect hardens in air and forms a covering on the body of the insect. This covering or the nest forms a continuous incrustation on the branches of the host trees. Lac is collected by scraping the incrustation from the branches of the trees.
21 citations