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Polypyrrole/Biopolymer Hybrid Coatings
Published in S.K. Dhawan, Hema Bhandari, Gazala Ruhi, Brij Mohan Singh Bisht, Pradeep Sambyal, Corrosion Preventive Materials and Corrosion Testing, 2020
S.K. Dhawan, Hema Bhandari, Gazala Ruhi, Brij Mohan Singh Bisht, Pradeep Sambyal
Ajay Daniel from Research Nester has elaborated that biopolymers are biodegradable polymers that do not contaminate the water resources like the traditional polymers as shown in schematic Figure 6.1. They are sustainable and renewable polymers which emit less amount of carbon dioxide in the environment. The growing demand for biopolymer as eco-friendly alternatives is anticipated to drive the growth of the biopolymer market over the forecast period. Apart from the above-mentioned applications, some of the biopolymers like gum acacia, chitosan, alginate, tragacanth gum, starch, etc., exhibit good corrosion inhibition properties (Prabhu and Rao 2013). Chitosan is found in the shells of crustaceans, such as lobsters, crabs shrimps and even in many other organisms like insects and fungi. It is one of the most abundant biodegradable materials in the world. Gum acacia is a natural gum consisting of the hardened sap of various species of the acacia tree. Gum arabic (Figure 6.2) consists of a mixture of lower relative molecular mass polysaccharide and higher molecular weight hydroxyproline-rich glycoprotein.
A comparative study between strength and durability of bentonite and natural gum stabilised sand
Published in Geomechanics and Geoengineering, 2022
Shamshad Alam, Assefa Weldu Gebremedhin, Hika Wachila Atomsa, Afzal Husain Khan
The natural gum (Guar gum and Xanthan gum) was applied to the sand in the form of solution. During the compaction, the gum solution with 0.5%, 1.0%, 1.5%, and 2.0% gum is used in place of water. The addition of the natural gum solution in the sand results in an increase of maximum dry unit weight up to the natural gum percentage of 1.5%, whereas further increase in gum percentage decreases the maximum dry unit weight (Figure 2). The maximum dry unit weight of the sand stabilised with solution containing 0.5% GG is observed as 15.99kN/m3, which increased to 16.38kN/m3 for the solution with 1.5% GG (Figure 2). Similarly, the sand stabilised with solution containing 0.5% XG is observed as 15.89kN/m3, which increased up to 16.19kN/m3 in case of the solution containing 1.5% XG (Figure 2). Figure 2 also reveals that the sand stabilised with Guar gum gives higher maximum dry unit weight compared to Xanthan gum up to 1.5%. However, the maximum dry unit weight at higher percentage (2.0%) of GG and XG is very close to each other (Figure 2). Few researchers reported 1.0% XG and 0.5% GG as an optimum percentage for maximum value of dry unit weight of biopolymer-treated sand (Qureshi et al. 2017, Ayeldeen et al. 2017). However, it may be mentioned here that result for 1.5% XG has not been presented by Qureshi et al. (2017). However, Swain et al. (2018) reported a continuous decrease in maximum dry density of biopolymer-treated dispersive soil, whereas Singh and Das (2019) reported 0.2% XG to achieve maximum value of dry unit weight of swelling soil.
Effect of neem gum on water sorption, biodegradability and mechanical properties of thermoplastic corn starch-based packaging films
Published in Indian Chemical Engineer, 2022
M. Anubha, R. Saranya, C. Chandrasatheesh, J. Jayapriya
The thickness of a film influences its properties and should be controlled to ensure uniformity in the polymeric matrix [27]. Table 1 presents the thickness of the CS-Gly and CS-Gly-NG films. In general, plasticisers increase the mobility of the amylase and amylopectin chains, thereby overcoming the opposite effect of re-crystallization and increasing the film flexibility [28,29]. The film thickness varied from 0.13 mm to 0.16 mm, and the gum concentration had no significant impact (One way ANOVA, P > 0.05). The similar thickness of the control film (CS-Gly) and those with NG at different concentrations signified that neem gum addition did not add free volume to CS-Gly. Film thickness is influenced by several factors, including the filmogenic solution composition and processing conditions (time and temperature of starch gelatinisation, cast-drying temperature, etc.). The addition of a natural gum to CS-Gly did not create any additional free volume, and thus the thickness was maintained. However, it re-structured the intermolecular polymer chain networks among the different polysaccharides, thereby changing the tensile strength and flexibility of the film (Table 1). In addition to intermolecular forces of attraction, the extent of possible crosslinking may be attributed to the major compositional contributors of neem gum (i.e. galactose) and cornstarch (i.e. amylopectin) in the presence of glycerol.
Sustainable plant-based bioactive materials for functional printed textiles
Published in The Journal of The Textile Institute, 2021
Alka Madhukar Thakker, Danmei Sun
Similarly, Degummed and bleached proteinic silk fabric was the block, screen, or stencil printed with natural dyes dolu, mahua, Indian madder, Khair, haritaki, lac, tea, pomegranate, annatto, Indigo, Haldi, and onion. The prime coloring pigment present in the natural dye were chrysophanic acid, quercetin dihydroquercetin, purpurin, catechin, elagitannic acid, laccaic acid, theaflavin and thearubigins, ellagitannin-flavogallol, bixin and nor-bixin, indigotin, curcuminoids, curcumin, quercetin, respectively. Natural gum indulka was utilized as a thickener. Metallic mordants were mixed along namely aluminum, ferrous, and copper sulfates. Acidic pH of 4.5 was maintained for proteinic fabric printing. The printed and dried fabrics were steamed at 100 °C for 30 min. Washed in non-ionic soap and air-dried. A good wash, light, and rub fastness were obtained except for Haldi and annatto (Roy, 2015). The plant phytochemicals play a vital role in imparting functional properties to the treated fabrics however the study overlooks the same.