Haoming Mo^1,*, Junhao Ding¹, Xu Song¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.011375

Abstract Triply periodic minimal surface (TPMS) shell-lattices are attracting increasing attention because of their exceptional mechanical and geometric characteristics. Additive manufactured TPMS structures using thermoplastic polyurethane (TPU) have great application potential in energy absorptions, for which the mechanical properties can be conveniently adjusted to meet diverse requirements. Nevertheless, there is a need for further improvement in the stability and adjustability of energy absorption capacity. This is due to the significant impact of the buckling effect and induced stress fluctuations when the structure is subjected to compression. To alleviate the buckling effect and tune the capability of… More >

Jaewook Lee¹, Byung-Dae Park^1,*, Qinglin Wu²

Journal of Renewable Materials, Vol.12, No.7, pp. 1187-1205, 2024, DOI:10.32604/jrm.2024.049948 - 21 August 2024

Abstract Lignin is the most abundant aromatic natural polymer, and receiving great attention in replacing various petroleum-based polymers. The aim of this study is to investigate the feasibility of technical lignin as a polyol for the synthesis of non-isocyanate polyurethane (NIPU) adhesives to substitute current polyurethane (PU) adhesives that have been synthesized with toxic isocyanate and polyols. Crude hardwood kraft lignin (C-HKL) was extracted from black liquor from a pulp mill followed by acetone fractionation to obtain acetone soluble-HKL (AS-HKL). Then, C-HKL, AS-HKL, and softwood sodium lignosulfonate (LS) were used for the synthesis of technical lignin-based… More > Graphic Abstract

Hong Pang¹, Ao Lu¹, Ming Xiong¹, Chen Chen¹, Xian Cao¹, Xiong Xu^2,3,*, Jing Wang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 1063-1074, 2024, DOI:10.32604/fdmp.2023.044000 - 07 June 2024

Abstract Conventional repairing methods for asphalt pavement have some inconveniences, such as insufficient strength, and are typically time-consuming. To address these issues, this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes. A series of composite modified asphalt binders with 10% crumb rubber (CR) and different dosages (0%, 1%, 3%, 5%) of polyurethane (PU) are examined to determine the optimized binder. Subsequently, the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties, such as moisture-induced damage, high-temperature deformation, and More >

Laima Vevere^*, Beatrise Sture, Vladimir Yakushin, Mikelis Kirpluks, Ugis Cabulis

Journal of Renewable Materials, Vol.12, No.3, pp. 585-602, 2024, DOI:10.32604/jrm.2024.047350 - 11 April 2024

Abstract Cryogenic insulation material rigid polyurethane (PU) foams were developed using bio-based and recycled feedstock. Polyols obtained from tall oil fatty acids produced as a side stream of wood biomass pulping and recycled polyethylene terephthalate were used to develop rigid PU foam formulations. The 4th generation physical blowing agents with low global warming potential and low ozone depletion potential were used to develop rigid PU foam cryogenic insulation with excellent mechanical and thermal properties. Obtained rigid PU foams had a thermal conductivity coefficient as low as 0.0171 W/m·K and an apparent density of 37–40 kg/m³. The developed… More > Graphic Abstract

Fatemeh Hassani Khorshidi¹, Saeed Kazemi Najafi¹, Farhood Najafi^2,*, Antonio Pizzi^3,*, Dick Sandberg⁴, Rabi Behrooz¹

Journal of Renewable Materials, Vol.12, No.2, pp. 305-323, 2024, DOI:10.32604/jrm.2023.043953 - 11 March 2024

Abstract The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin nano-particles. For this purpose, the prepared coatings were applied to pine wood surfaces and weathered artificially. Subsequently, color and gloss of the coatings were measured before and after the weathering test. Field emission scanning electron microscopy (FE-SEM) micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 nm. Nuclear magnetic resonance (¹³C-NMR) spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based polyurethane. Differential calorimetric analysis (DSC) test revealed… More > Graphic Abstract

SIVARAJ SUDHAHAR^a,f, UMAMAHESWARI G^b, JAYA PRAKASH ALLA^c, RAGHAVA RAO JONNALAGADDA^d, SUGUNA LAKSHMI^e, SANJEEV GUPTA^f,*

Journal of Polymer Materials, Vol.40, No.1-2, pp. 33-45, 2023, DOI:10.32381/JPM.2023.40.1-2.3

Abstract Leather manufacturing process involves a lot of waste disposal which pollutes environment, some of the processes are inevitable. In the present investigation, 3D printing technology was used to reduce the wastage and to cover defective regions in leather. The present study focuses on synthesis of acrylic binder using emulsion polymerization technique. These binders were analysed for solid content for better optimisation of the amount of binder to be utilised for finishing operation. The experimental binder was prepared with 26% solids. Particle size and thermogravimetric analyses were carried out to understand the size and shape of… More >

Lei Yang¹, Guangyan Huang^1,2,*, Tao Wang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.09759

Abstract In order to evaluate the blast mitigation effect of polyurethane foam in cylindrical explosion containment vessels (CECVs), a three-dimensional numerical simulation model was established. The Structured Arbitrary Lagrange-Euler (S-ALE) algorithm was applied in current simulations to define the coupling contact between TNT and Lagrange algorithm. The numerical model was verified by comparing the dynamic deformation and permanent deformation of the experiments. Based on the numerical simulation model after verification, the influence of polyurethane foam filling inside CECVs on the mitigation effect was investigated. The results revealed that compared with the ALE algorithm, the numerical simulations… More >

Elham Azadeh¹, Antonio Pizzi^1,2,*, Christine Gerardin-Charbonnier^1,*, Philippe Gerardin¹

Journal of Renewable Materials, Vol.11, No.6, pp. 2823-2848, 2023, DOI:10.32604/jrm.2023.027651 - 27 April 2023

Abstract Non-isocyanate polyurethane (NIPU) foams from a commercial hydrolysable tannin extract, chestnut wood tannin extract, have been prepared to determine what chemical species and products are taking part in the reactions involved. This method is based on two main steps: the reaction with dimethyl carbonate and the formation of urethane bonds by further reaction of the carbonated tannin with a diamine-like hexamethylene diamine. The hydroxyl groups on the tannin polyphenols and on the carbohydrates intimately linked with it and part of a hydrolysable tannin are the groups involved in these reactions. The carbohydrate skeleton of the… More > Graphic Abstract

Saeed Kazemi Najafi¹, Farhood Najafi², Antonio Pizzi^3,*, Fatemeh Hassani Khorshidi^1,*, Rabi Behrooz¹

Journal of Renewable Materials, Vol.11, No.5, pp. 2171-2189, 2023, DOI:10.32604/jrm.2023.027835 - 13 February 2023

Abstract Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms, especially carbon-carbon and carbon-hydrogen. These compounds are mainly used as reactants to make other polymers. Among biopolymers, lignin is regarded as the base of a new polymer in polyol construction. The present study aimed to investigate the effects of amine type (diethylenetriamine and ethylenediamine) on the modification of lignin-based polyols, so as to provide an alternative to petroleum polyols and, in turn, increase functional groups and reduce their harm to humans’ health and the environment. To this aim, first,… More > Graphic Abstract

Henghui Deng^1,2, Jingyi Lu^1,2, Dunsheng Liang^1,2, Xiaomin Wang^1,2, Tongyao Wang^1,2, Weihao Zhang^1,2, Jing Wang^3,*, Chaoqun Zhang^1,2,*

Journal of Renewable Materials, Vol.11, No.3, pp. 1209-1222, 2023, DOI:10.32604/jrm.2022.023371 - 31 October 2022

Abstract In this study, acrylic acid was used as a neutralizer to prepare bio-based WPU with an interpenetrating polymer network structure by thermally induced free radical emulsion polymerization. The effects of the content of acrylic acid on the properties of the resulting waterborne polyurethane-poly (acrylic acid) (WPU-PAA) dispersion and the films were systematically investigated. The results showed that the cross-linking density of the interpenetrating network polymers was increased and the interlocking structure of the soft and hard phase dislocations in the molecular segments of the double networks was tailored with increasing the content of acrylic acid, More > Graphic Abstract