Gang Wang, Xiaohui Liu, Changhong Mi, Huijuan Fan, Bo Xu and Xuefeng Bai
The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the oligomers as…
Abstract
Purpose
The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the oligomers as heat-resistant modifiers.
Design/methodology/approach
PPhBS was synthesized by direct co-condensation of boric acid (BA) and phenyltriethoxysilane (PTEOS). The structural evolution of PPhBS at high temperature was investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and 29Si nuclear magnetic resonance (NMR) spectroscopy. In addition, the change in the morphology of the PPhBS powder was examined to demonstrate the evolution of the chemical bonds, and the hydrolytic stability of PPhBS was investigated by a combination of X-ray diffraction (XRD) analysis, measurement of the mass loss in water and FTIR spectroscopy.
Findings
The results revealed that a cross-linking network was gradually formed with increasing temperature through the condensation of the residual hydroxyl groups in PPhBS, and the Si-OH and B-OH bonds remained even at a high temperature of 450°C. Furthermore, heat treatment improved the hydrolytic stability of the oligomer. The hydrolysis of the B-O-B bonds in PPhBS was reversible, whereas the Si-O-Si and Si-O-B bonds were highly resistant to hydrolysis.
Practical implications
The prepared PPhBS can be used as a heat-resistant modifier in adhesives, sealants, coatings and composite matrices.
Originality/value
Investigation of the structural evolution of a polyborosiloxane at high temperature by DRIFTS is a novel approach that avoided interference from moisture in the air. The insoluble mass fraction and the FTIR spectrum of PPhBS washed with water were used to investigate the hydrolytic stability of PPhBS.
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Dayong Zhang, Xiaohui Liu, Xuefeng Bai, Gang Wang, Liping Rong, Ying Zhao, Xin Li, Jinhua Zhu and Changhong Mi
The purpose of this study is to investigate the heat resistance and heat-resistant oxygen aging of 4-nitrophthalonitrile-etherified cardanol-phenol-formaldehyde (PPCF) to further…
Abstract
Purpose
The purpose of this study is to investigate the heat resistance and heat-resistant oxygen aging of 4-nitrophthalonitrile-etherified cardanol-phenol-formaldehyde (PPCF) to further use and develop the resin as the matrix resin of high-temperature resistant adhesives and coatings.
Design/methodology/approach
PPCF resin was synthesized by 4-nitrophthalonitrile and cardanol-phenol-formaldehyde (PCF). The structures of PPCF and PCF were investigated by Fourier transform infrared, differential scanning calorimetry and proton nuclear magnetic resonance. In addition, the heat resistance and processability of PPCF and PCF resins were studied by dynamic mechanical analysis, thermogravimetric analysis, scanning electronic microscopy (SEM), X-ray diffraction (XRD) techniques and rheological studies.
Findings
The results reveal that PPCF forms a cross-linked network at a lower temperature. PPCF resin has excellent resistance under thermal aging in an air atmosphere and that it still had a certain residual weight after aging at 500°C for 2 h, whereas the PCF resin is completely decomposed.
Originality/value
4-Nitrophthalonitrile was introduced into PCF resin, and XRD and SEM were used to investigate the high temperature residual carbon rate and heat-resistant oxygen aging properties of PPCF and PCF resins.
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The purpose of this paper lies in the combination of fuzzy set and interval grey set, namely, considering the fuzzy set theory, rough set theory and grey system theory. The paper…
Abstract
Purpose
The purpose of this paper lies in the combination of fuzzy set and interval grey set, namely, considering the fuzzy set theory, rough set theory and grey system theory. The paper then presents a unified form (or symbol system) which can be more useful to describe a wide variety of theories.
Design/methodology/approach
Considering the lower bounds and upper bounds of interval grey set are classical set, this paper draws lessons from the classical set to fuzzy set transition mode which was advanced by Professor Zadeh. The paper puts forward the concept of interval fuzzy set, and then relaxes the constraints of the lower bound of interval fuzzy set to make it more widely used in actual uncertain problems.
Findings
For the examples which have been given in the paper, interval fuzzy set and its three theorems are proved practical and flexible.
Practical implications
The theorems proved in the paper can be used as a useful extension to the classical fuzzy set, which can also be applied to fuzzy clustering, fuzzy classification, fuzzy pattern recognition and so on.
Originality/value
The paper puts forward the concept of interval fuzzy set and the three theorems of interval fuzzy set and proves their practicability and flexibility. The theorems can be used for further study on interval fuzzy set.
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The purpose of this paper is to investigate the impact of fairness concern on the optimal pricing, carbon emission reduction (CER), green marketing efforts (GME) and utility of…
Abstract
Purpose
The purpose of this paper is to investigate the impact of fairness concern on the optimal pricing, carbon emission reduction (CER), green marketing efforts (GME) and utility of supply chain members in a two-echelon low-carbon supply chain composed of one manufacturer and one retailer. First, three basic models that consider the manufacturer’s different attitudes toward the retailer’s fairness concern are constructed. The optimal decisions of these models are obtained. Second, these optimal solutions are compared, and the effects of some key parameters including fairness concern on the optimal decisions and utility are examined for the three models. Furthermore, the manufacturer may misestimate the retailer’s fairness concern; therefore, an extended model is proposed.
Design/methodology/approach
The authors adopt the manufacturer-led Stackelberg game theoretic framework, where the manufacturer decides the wholesale price and CER level and, then, the retailer determines the retail price and GME.
Findings
The results show that fairness concern has a negative impact on the wholesale price, the level of CER and GME, and fairness concern are not always beneficial for maximizing utility, although it is related to whether the manufacturer pays attention to the retailer’s fairness concern. The manufacturer will gain more utility when considering the fairness concern of retailers than non-consideration. Overestimating or underestimating the fairness concern of the retailers does not lead to benefits for the manufacturer.
Research limitations/implications
This study has the following two limitations that need to be addressed in future research. First, the authors only consider the fairness concern of a single retailer but not peer-induced fairness among multiple competing retailers, which can be taken into account in future studies. Second, the demand function is linearly related to price, CER and GME. Because of the uncertainty of market information, the uncertainty demand function can be further considered.
Originality/value
This paper simultaneously considers the factors CER, GME and fairness concern. The utility function of the retailer is established according to taking the Nash bargaining solution as a fairness reference point, and four different models are constructed and compared.
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The purpose of this paper is to construct some negative grey relational analysis models to measure the relationship between reverse sequences.
Abstract
Purpose
The purpose of this paper is to construct some negative grey relational analysis models to measure the relationship between reverse sequences.
Design/methodology/approach
The definition of reverse sequence has been given at first based on analysis of relative position and change trend of sequences. Then, several different negative grey relational analysis models, such as the negative grey similarity relational analysis model, the negative grey absolute relational analysis model, the negative grey relative relational analysis model, the negative grey comprehensive relational analysis model and the negative Deng’s grey relational analysis model have been put forward based on the corresponding common grey relational analysis models. The properties of the new models have been studied.
Findings
The negative grey relational analysis models proposed in this paper can solve the problem of relationship measurement of reverse sequences effectively. All the new negative grey relational degree satisfying the requirements of normalization and reversibility.
Practical implications
The proposed negative grey relational analysis models can be used to measure the relationship between reverse sequences. As a living example, the reverse incentive effect of winning Fields Medal on the research output of winners is measured based on the research output data of the medalists and the contenders using the proposed negative grey relational analysis model.
Originality/value
The definition of reverse sequence and the negative grey similarity relational analysis model, the negative grey absolute relational analysis model, the negative grey relative relational analysis model, the negative grey comprehensive relational analysis model and the negative Deng’s grey relational analysis model are first proposed in this paper.