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The Influence of Azidated Glycerol as a New Low Temperature Stabilizer on the Colloidal Properties of Natural Rubber Latex: For Latex Marine Transportation. Polymers (Basel) 2023; 15:polym15030698. [PMID: 36771999 PMCID: PMC9918890 DOI: 10.3390/polym15030698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Natural rubber latex (NRL) is normally transported to a destination in colloid/liquid form. It requires large storage containers such as drums and the probability of latex leakage during transportation is high. This is prevalent especially when transporting latex by sea. To prevent latex spillage, the liquid form of NRL is transformed into solid/frozen latex by freezing. However, the coagulation/destabilization of NRL by freezing has been acknowledged as a problem for years. Therefore, this study proposed a new low temperature stabilizer named azidated glycerol (AG) to be incorporated in NRL liquid before the freezing process. AG was prepared by a chemical reaction of pure glycerol with sodium azide. NRL containing AG was then frozen at a temperature of -4 °C. After 24 h of freezing, the frozen latex was thawed at ambient temperature for 1 h followed by heating in a water bath at 40 °C for another 1 h. The regenerated latex was then allowed to stand at room temperature before testing. The effect of AG on the colloid properties before and after the freeze-thaw processes was studied. The production of AG was confirmed by the appearance of a peak in the range of 2160-2120 cm-1, corresponding to N=N=N stretching, confirming the introduction of an azide group into the glycerol molecule. Modifying NRL with AG did not significantly influence the TSC of latex. Increasing the AG content up to 0.4 phr resulted in an increase in MST from 699 s to 828 s. An AG content of 0.2 phr resulted in the highest anionically stabilized latex as indicated by zeta potential values of -59.63 mV (before freezing) and -56.27 mV (after thawing). It is concluded that the AG produced in this study can be used as an anti-freeze stabilizer for NRL and is suitable for latex marine transportation.
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Construction, Physical Properties and Foaming Behavior of High-Content Lignin Reinforced Low-Density Polyethylene Biocomposites. Polymers (Basel) 2022; 14:polym14132688. [PMID: 35808737 PMCID: PMC9269087 DOI: 10.3390/polym14132688] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/18/2022] [Accepted: 06/28/2022] [Indexed: 02/05/2023] Open
Abstract
Lignin was chemically modified with oligomeric polyethylene (oPE) to form oPE-grafted lignin (oPE-g-lignin) via lignin surface acylation and a radical coupling reaction with oPE. Then, pristine lignin and oPE-g-lignin were successfully compounded with low-density polyethylene (LDPE) through a typical compounding technique. Due to the oligomeric polyethylene chains grafted to the lignin’s surface, the interfacial adhesion between the lignin particles and the LDPE matrix was considerably better in the oPE-g-lignin/LDPE biocomposite than in the pristine-lignin/LDPE one. This demonstrated that oPE-g-lignin can serve as both a biodegradable reinforcing filler, which can be loaded with a higher lignin content at 50 wt-%, and a nucleating agent to increase the crystallization temperature and improve the tensile characteristics of its LDPE biocomposites. Moreover, the foamability of the lignin-reinforced LDPE biocomposites was studied in the presence of a chemical blowing agent (azodicarbonamide) with dicumyl peroxide; for an oPE-g-lignin content up to 20 wt-%, the cell size distribution was quite uniform, and the foam expansion ratios (17.69 ± 0.92) were similar to those of the neat LDPE foam (17.04 ± 0.44).
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Wood Surface Modification—Classic and Modern Approaches in Wood Chemical Treatment by Esterification Reactions. COATINGS 2020. [DOI: 10.3390/coatings10070629] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Wood surface modification is a comprehensive concept which, in time, turned out to be as successful as challenging when it comes to improve the resistance of wood during its life cycle in both indoor and outdoor applications. The initial approaches have aimed at simple methods with immediate results. Nowadays, the paradigm has slightly changed due to the scientific and technical advances, and some methods has become intermediate stages in more complex processes, after being used, for long time, as stand-alone procedures. The esterification was employed as a convenient method for wood surface modification due to the high amount of free hydroxyl groups available at the surface of wood and other lignocellulosic materials. Therefore, different esterification approaches were tested: activated condensation with carboxylic acids (monocarboxylic, as well as dicarboxylic acids, fatty acids, etc.) in the presence of condensation activating agents (such as trifluoroacetic anhydride); reaction with β-halogen-substituted carboxylic acids; esterification using carboxylic acids derivatives (acyl chlorides, anhydrides) or even multifunctional carboxylic acids (i.e., tricine). Thus, wood with improved dimensional stability and weathering resilience, higher fire resistance, enhanced hydrophobic character, and mechanical durability was obtained. This paper offers an overview of some of the most recent advances reported in the field, presented in a systematic manner, using the type of reaction as classification criterion. The main improvements will be outlined in a critical assessment in order to provide an useful tool for a wise choice in future applications.
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Mahata D, Jana M, Jana A, Mukherjee A, Mondal N, Saha T, Sen S, Nando GB, Mukhopadhyay CK, Chakraborty R, Mandal SM. Lignin-graft-Polyoxazoline Conjugated Triazole a Novel Anti-Infective Ointment to Control Persistent Inflammation. Sci Rep 2017; 7:46412. [PMID: 28401944 PMCID: PMC5401907 DOI: 10.1038/srep46412] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/01/2017] [Indexed: 11/26/2022] Open
Abstract
Lignin, one of the most abundant renewable feedstock, is used to develop a biocompatible hydrogel as anti-infective ointment. A hydrophilic polyoxazoline chain is grafted through ring opening polymerization, possess homogeneous spherical nanoparticles of 10-15 nm. The copolymer was covalently modified with triazole moiety to fortify the antimicrobial and antibiofilm activities. The hydrogel was capable of down regulating the expression level of IL-1β in LPS induced macrophage cells, and to cause significant reduction of iNOS production. It supported cellular anti-inflammatory activity which was confirmed with luciferase assay, western blot, and NF-κB analysis. This novel lignin-based hydrogel tested in-vivo has shown the abilities to prevent infection of burn wound, aid healing, and an anti-inflammatory dressing material. The hydrogel reported here provides a new material platform to introduce a cost-effective and efficient ointment option after undertaking further work to look at its use in the area of clinical practice.
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Affiliation(s)
- Denial Mahata
- Central Research Facility, Rubber Technology Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, WB, India
| | - Malabendu Jana
- Department of Neurological Sciences, Rush University Medical Centre, Chicago, IL, USA
| | - Arundhuti Jana
- Department of Neurological Sciences, Rush University Medical Centre, Chicago, IL, USA
| | - Abhishek Mukherjee
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Nibendu Mondal
- OMICS Laboratory, Department of Biotechnology, University of North Bengal, Siliguri-734 013, WB, India
| | - Tilak Saha
- OMICS Laboratory, Department of Biotechnology, University of North Bengal, Siliguri-734 013, WB, India
| | - Subhajit Sen
- OMICS Laboratory, Department of Biotechnology, University of North Bengal, Siliguri-734 013, WB, India
| | - Golok B. Nando
- Central Research Facility, Rubber Technology Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, WB, India
| | - Chinmay K. Mukhopadhyay
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Ranadhir Chakraborty
- OMICS Laboratory, Department of Biotechnology, University of North Bengal, Siliguri-734 013, WB, India
| | - Santi M. Mandal
- Central Research Facility, Rubber Technology Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, WB, India
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