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Article
Publication date: 5 September 2016

Wei Li, Guilong Xu, Buqin Xu, Yi Wang, Jin Yang and Jian Hu

The flammability of epoxy resin is a major disadvantage in applications that require flame resistance. Epoxy monomers and hardeners containing flame-retardant elements are…

Abstract

Purpose

The flammability of epoxy resin is a major disadvantage in applications that require flame resistance. Epoxy monomers and hardeners containing flame-retardant elements are molecularly incorporated in the resin network are expected to exhibit better flame resistance than those borne on an additive approach. In recent years, because of health and environmental regulation, the use of waterborne coatings has received many attentions. However, waterborne epoxy resin curing agent with excellent flame retardancy has been seldom reported. The paper aims to study the preparation of waterborne P-N-containing epoxy resin curing agent and its performances (P-N – phosphorous and nitrogen).

Design/methodology/approach

Waterborne P-N-containing epoxy curing agent was prepared in this study using reactive flame retardant 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-xa-10-phosphaphenanthrene-10-oxide, liquid epoxy resin, triethylenetetramine and butyl glycidyl ether at the mole ratio of 1.0:2.0:2.0:2.0.

Findings

The results show that the epoxy thermoset from the prepared P-N-containing curing agent presents good flame retardancy and can pass the V-1 rating, and the cured epoxy thermoset film presents excellent performances such as water resistance, adhesion, impact resistance and pencil hardness. This study provides useful suggestions for the application of the water-borne flame retardancy epoxy resins in coating industry.

Research limitations/implications

Each step of products during the preparation of waterborne P-N-containing epoxy curing agent cannot be accurately tested.

Originality/value

This method for synthesis of waterborne P-N-containing epoxy curing agent is novel and could be used for various applications in epoxy coating industry.

Details

Pigment & Resin Technology, vol. 45 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 4 December 2019

Xinyue Liang, Hui Qiao, Guilong Xu, Yanchong Zhang, Yun Liang and Jian Hu

The flammability of poly-acrylate (PA) resin is a major disadvantage in applications that require flame resistance. Many studies, including the authors’ previous study…

Abstract

Purpose

The flammability of poly-acrylate (PA) resin is a major disadvantage in applications that require flame resistance. Many studies, including the authors’ previous study, have proved that covalent-incorporated phosphorous-containing (P-containing) monomer onto the PA resin can exhibit better flame resistance than that by an additive approach. However, other properties such as thermal stability, coating properties are still deteriorated. To further improve the flame-retardancy and other comprehensive properties of the P-containing PA resin, in this study, melamine formaldehyde(MF) resin was used not only as a curing agent to enhance the coating properties of the PA resin, but also as a nitrogen-containing (N-containing) resin to form a P-N synergistic effect and therefore further improve its flame retardancy.

Design/methodology/approach

Epoxy resin phosphorous acid-modified (EPPA-modified) PA (EPPA-PA) resin was first prepared and then using MF resin as curing agent. The flame retardancy of the cured resin was tested by the limiting oxygen index (LOI) and UL 94 methods. The thermal stability of the cured resin was studied by TGA. The coating technology such as adhesion property, pencil hardness and anti-solvent properties were characterized according to methods of International Standards ISO2409-1992, ISO 15184-1998 and ISO-15184-2012, respectively. The micro-char morphology of the char residue was observed by SEM.

Findings

The results showed that by using MF resin as curing agent has provided the PA resin with excellent coating properties and thermal stability, but also gave a P-N synergistic effect which has greatly enhanced the flame retardancy of the cured resin. The cured resin system containing only 1.7 Wt.% P content and 5.3 Wt.% N content can reach a LOI of 26.9 per cent and pass the V-0 rating in the UL-94 test.

Research limitations/implications

This resin system releases formaldehyde due to the MF resin.

Practical implications

It is expected that the large-scale production of this EPPA-PA resin cured by MF resin system will enable practical industrial applications.

Originality/value

This method for the synthesis of a P- and N-containing PA resin system is newfangled.

Details

Pigment & Resin Technology, vol. 49 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 4 January 2019

Buqin Xu, Guilong Xu, Hui Qiao, Yun Liang, Jin Yang and Jian Hu

The flammability of poly-acrylate (PA) resin is a major disadvantage in applications that require flame resistance. It has been reported that a flame-retardant PA resin…

Abstract

Purpose

The flammability of poly-acrylate (PA) resin is a major disadvantage in applications that require flame resistance. It has been reported that a flame-retardant PA resin could be prepared by covalent incorporate phosphorous containing monomer with vinyl group via free radical polymerization, and the prepared modified PA resin is expected to exhibit better flame resistance than those by an additive approach. However, the phosphorus-containing monomers reported previously are made from expensive or toxic materials, and the production procedure is tedious and under harsh reaction conditions, which are not feasible for industrial application. Therefore, the purpose of this paper is the preparation of flame-retardant PA resin modified by epoxy resin phosphorous acid (EPPA) and the study of its flame retardancy.

Design/methodology/approach

EPPA is first prepared by epoxy resin E-51 and phosphorous acid and then used to prepare phosphorous containing PA resin by free radical polymerization. The flame retardancy of the prepared EPPA-modified PA (EPPA-PA) resin is studied.

Findings

The results show that EPPA can graft onto the PA polymer chain by free radical polymerization, the flame retardancy of the EPPA-PA resin increases as the EPPA content increasing. The flame retardancy of EPPA-PA resin prepared reaches 27.8% and can pass the V-0 rating in the UL-94 test when EPPA content is 30.0%. SEM and EDS results indicate that phosphorous element in the EPPA-PA resin shows a condensed-phase flame retardant effect.

Research limitations/implications

The grafting degree of EPPA cannot be accurately tested.

Practical implications

It is expected that the large-scale production of this epoxy resin phosphoric acid modified PA resin will enable practical industrial applications.

Originality/value

This method for synthesis of epoxy resin phosphoric acid modified PA resin is newfrangled.

Details

Pigment & Resin Technology, vol. 48 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 27 September 2018

Jian Hu, Naigang Cui, Yuliang Bai and Yunhai Geng

The purpose of this paper is to present a novel guidance law that is able to control the impact time while the seeker’s field of view (FOV) is constrained.

Abstract

Purpose

The purpose of this paper is to present a novel guidance law that is able to control the impact time while the seeker’s field of view (FOV) is constrained.

Design/methodology/approach

The new guidance law is derived from the framework of Lyapunov stability theory to ensure interception at the desired impact time. A time-varying guidance gain scheme is proposed based on the analysis of the convergence time of impact time error, where finite-time stability theory is used. The circular trajectory assumption is adopted for the derivation of accurate analytical estimation of time-to-go. The seeker’s FOV constraint, along with missile acceleration constraint, is considered during guidance law design, and a switching strategy to satisfy it is designed.

Findings

The proposed guidance law can drive missile to intercept stationary target at the desired impact time, as well as satisfies seeker’s FOV and missile acceleration constraints during engagement. Simulation results show that the proposed guidance law could provide robustness against different engagement scenarios and autopilot lag.

Practical implications

The presented guidance law lays a foundation for using cooperative strategies, such as simultaneous attack.

Originality/value

This paper presents further study on the impact time control problem considering the seeker’s FOV constraint, which conforms better to reality.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 3 April 2017

Lian-jiang Wei, Jian-kun Hu, Xin-rong Luo and Wei Liang

The purpose of this paper is to devise novel methods for effectively reducing China’s coal mining accidents via analysis of the relation between coal mine safety…

Abstract

Purpose

The purpose of this paper is to devise novel methods for effectively reducing China’s coal mining accidents via analysis of the relation between coal mine safety production and social factors.

Design/methodology/approach

The variations and characteristics of the safety production for coal mines in China from 1949 to 2013 are studied via induction and statistical analysis of data from the perspective of mortality rate per million tons, raw coal output and death tolls. It is analyzed that the relationship between coal mine safety production level and social economic, safety investment via SPSS.

Findings

Analysis of the coal mine safety management evolution across the 64 years after the founding of China demonstrates that China’s coal mine safety management evolution is partitioned into four stages, and there is the coupling relation between coal mine safety production and structure the of coal industry, government supervision and safety investment. By discussing the similarity between China and America in coal mine safety management evolution, it is found that the rapid increase in the number of accidents during the transformation from agricultural to industrial society is not accidental.

Practical implications

The suggestions in this paper are helpful to improve the current safety situation in China’s coal mines and provide management experience to other coal mining countries.

Originality/value

Based on present and future socioeconomic development, it is proposed that the coal mine safety situation can be further enhanced by properly adjusting the structure of the coal industry, strengthening supervision and ensuring safety investment.

Details

International Journal of Energy Sector Management, vol. 11 no. 1
Type: Research Article
ISSN: 1750-6220

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Article
Publication date: 1 January 2007

Hu Weibing, Chen Xing and He Jian

Based on the character of R‐C frame, the calculation formula of VED is derived from the sub‐structure plan of lateral resistant force, the definition of equivalent…

Abstract

Based on the character of R‐C frame, the calculation formula of VED is derived from the sub‐structure plan of lateral resistant force, the definition of equivalent stiffness matrix and equivalent additional viscoelastic force vector of VED is given and the seismic dynamic equation of R‐C frame controlled by VED is set up, the viscoelastic additional force vector of VED should be considered as outside load of structure and be calculated through the pseudo‐loading method, the programs of calculating the dynamic characteristic, calculating the elastic seismic response and calculating the elastic‐plastic seismic response of R‐C frame controlled by VED are compiled. Through the calculation of a inclined crossed R‐C frame, the results show that VED is effective in controlling the seismic response of frame and the pseudo‐loading method is reliable in the calculation.

Details

Multidiscipline Modeling in Materials and Structures, vol. 3 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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Article
Publication date: 1 February 2006

Zhou Xuesong, Luo Guo, Wang Yi Hu Jian and Zheng Chisong

In order to improve the interfacial adhesion between PBO fiber and epoxy resin, the surface modification method of chemical treatment was employed. It was demonstrated…

Abstract

In order to improve the interfacial adhesion between PBO fiber and epoxy resin, the surface modification method of chemical treatment was employed. It was demonstrated that the interfacial shear strength (IFSS) of the micro-composite system increased by 24% compared with the control sample, which was measured by the singer fiber pull-out test. Furthermore, the surface morphology of the fiber was investigated by SEM and the wettability between the sample and water was characterized by the droplet-shape profile.

Details

Research Journal of Textile and Apparel, vol. 10 no. 1
Type: Research Article
ISSN: 1560-6074

Keywords

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Case study
Publication date: 1 January 2011

Margie Parikh

Leadership development, career planning and management, management of start-ups, construction industry in India.

Abstract

Subject area

Leadership development, career planning and management, management of start-ups, construction industry in India.

Study level/applicability

Post graduate management courses, executive training programs/modules in leadership development; organizational culture and construction management.

Case overview

This case illustrates the shortcomings of both the management and leadership at a start-up business within a growing industry. The rapidly growing construction equipment manufacture and renting activity in India and the lack of structure, systems and resources characteristic of start-ups are complicated more by the fact that Itsun Heavy Industry India Pvt. Ltd (IHIIPL) was in India while its head quarter was in China. In exploring the diverse human, organizational and operational problems shadowing IHIIPL and their causes, students cannot only diagnose what went wrong and why for Dilip, but also sense how he could have handled these issues more effectively.

Expected learning outcomes

Dilip's case cautions managers against issues common to many industries and organizations and students will examine: self assessment and career choices: the case raises question of the gap between what was needed at IHIIPL and what skills and qualities Dilip brought to the job; leadership and leadership challenge: the case raises question of what kind of attitudes and actions constitute effective leadership; and managing the company performance for a start-up: Dilip faced a constant stream of operating problems: lack of procedures and systems, a non-supportive headquarter in China, inexperienced staff, shortages of resources and material and internal conflicts.

Supplementary materials

Teaching note.

Details

Emerald Emerging Markets Case Studies, vol. 1 no. 1
Type: Case Study
ISSN: 2045-0621

Keywords

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Article
Publication date: 8 March 2011

Jian‐Qiang Hu, Xin‐Lin Wang, Ge‐Lin Dai, Yi‐Wei Fei, Xian‐Yong Wei and Zhi‐Min Zong

Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However…

Abstract

Purpose

Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However, MoDDC‐containing lubricants may lose their ability to reduce friction over time, which may result from its concentration in oils below a critical concentration owing to oxidative degradation of MoDDC. Thus, in order to enhance the durability of the low friction performance of MoDDC, the paper aims to investigate good synergistic antioxidants with MoDDC.

Design/methodology/approach

The antioxidation properties of molybdenum dialkyldithiocarbamate (M 807) – and p,p‐dioctyldiphenylalmine (V 81) – or mixed octylated and butylated diphenylalmines (V 961)‐containing poly‐α‐olefin (PAO)‐derived lubricants were evaluated by differential scanning calorimetry (DSC) and modified penn state micro‐oxidation test (PMOT). DSC test measures incipient oxidation temperature (OT) and oxidation induction time (IT) of the lubricant at high temperatures and the oxidation stability of oil weight loss is measured by PMOT. Moreover, the oxidized samples were analyzed by Fourier transform infrared (FTIR) and electron spin resonance (ESR).

Findings

A DSC test shows that OT and IT of V 81‐ or V 961‐containing PAO were improved significantly by M 807 addition. A PMOT indicates that when combining with V 81 antioxidants, M 807 can also effectively reduce the increase in weight loss of PAO and deposits formed in oils. These results suggest that the M 807 shows a good antioxidative synergism with alkylated diphenylamine antioxidants. In addition, FTIR results from a PMOT confirm that the addition of M 807 can significantly enhance the oxidation IT of oils containing V 81 and inhibit formation of oxidation products including carbonyl bonds or hydroxyl group. ESR analysis from a PMOT indicates that M 807 may form stable radicals with arylamine by the coordination effect.

Originality/value

This paper provides simple and quick methods to evaluate synergistic antioxidation properties between different types of additives, and a mechanism of the inhibition involving a synergy was proposed. They can offer practical help in industrial applications and to an individual starting out on an academic career.

Details

Industrial Lubrication and Tribology, vol. 63 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 November 2006

Jian‐Qiang Hu, Xian‐Yong Wei and Zhi‐Min Zong

Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low…

Abstract

Purpose

Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex.

Design/methodology/approach

The complex of thiadiazole dimmer and polyglycol (DMS2‐GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test.

Findings

The additive DMS2‐GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does not corrode copper but coats the metal with a film, and could improve the anticorrosion of corrosive additives molybdenum dialkyldithiophosphate (MoDDP) and molybdenum dibutyldithiocarbamate (MoDTC) by forming protective films on rubbing surface, which contribute to improving corrosion inhibiting property of greases. Finally, the tribo‐chemical mechanism was proposed that thiadiazole dimer and polyglycol could coordinate with each other by polydentate surface interaction, which means thiadiazole rings interact with the metal surface, polyglycol affords a bridging technology linked thiadiazole dimmers so as to lighten loads and strengthen forces between thiadiazole dimmer moleculars.

Originality/value

This paper provides a good ashless additive which has good antiwear, extreme pressure and corrosion inhibiting properties, and fulfils an identified resources need, which can offer practical help in industrial applications and to an individual starting out on an academic career.

Details

Industrial Lubrication and Tribology, vol. 58 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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