Polyphenylene sulfide fabric with improved antibacterial properties and comprehensive performances by new polybenzoxazine based coating for protection applications

Polyphenylene sulfide (PPS) fabric is promising for personal protective equipment (PPE) due to its excellent mechanical properties. However, issues such as a lack of antibacterial properties, limits its applications, especially today when COVID-19 is a pandemic. Herein, we synthesize a new benzoxazine monomer (BTE) with ester and triazole groups and demonstrate its usage as a coating for comprehensive high-performance PPS fabric. The polymerized BTE exhibits an antibacterial rate of 77.4%, and outstanding flame-retardant properties (The Heat release capacity (HRC) value is 62 J g−1 K−1 and the Total heat release (THR) value is 9.4 kJ g−1). The mechanical performance and acid resistance of BTE-coated PPS fabric show excellent improvement. The tensile strength of the modified system rise by approximately 24.7%, reaching 8.6 MPa, while the corresponding Young's modulus increases by 51.7%, reaching 36.7 MPa, respectively, and after 72 h of acid treatment, the tensile strength retention rate reaches 91.7%. Furthermore, the BTE-coated PPS fabric demonstrates a complete change in wettability (the hydrophilic surface of PPS becomes hydrophobic for BTE-coated PPS) with only a slight reduction in the air permeability (260 mm s−1 for PPS and 198 mm s−1 for BTE coated PPS), making it an appealing material for PPE and demonstrating the potential of related materials for harsh environment protective systems.

Research on extremely short construction period of engineering project based on labor balance under resource tolerance.

Under the condition of resource tolerance, engineering construction projects face the problem of labor force balance in the working face. Notably, a deviation occurs between the distribution and certain demand of the labor force in the limited working face, which affects the realization of an extremely short construction period. To address this problem, we first introduced the stochastic coefficient of labor force equilibrium to measure the degree of labor balance. Second, a labor force equilibrium model with the realization goal of an extremely short construction period was established. Then, the standard particle swarm optimization (PSO) algorithm was improved from two perspectives to solve the proposed model. The update equation was rounded to solve practical project problems, and a dynamic variable inertia weight was adopted to ensure the PSO algorithm accuracy and convergence speed. Finally, through case analysis, we determined the extremely short construction period and best labor force distribution scheme. Moreover, the case results revealed that the established model is simple, operable and practical and that the proposed algorithm achieves a high search accuracy and efficiency in the model solution process. Overall, under the condition of resource tolerance, this study provides scientific and effective references for managers to realize an extremely short construction period.

Research on the factors of extremely short construction period under the sufficient resources based on Grey-DEMATEL-ISM.

Under the condition of sufficient resources, there are many factors affecting the realization of extremely short construction period of engineering construction projects. Based on literature review and questionnaire survey, this paper firstly selected 17 influencing factors from the five dimensions of design, management, technology, policy and environment. And the factor analytic hierarchy process model was established based on Grey-DEMATEL-ISM. The model introduced the improved grey system theory and combined decision-making trial and evaluation laboratory (DEMATEL) with interpretative structural modeling method (ISM). In addition, the model can not only identify the critical factors in the system, but also present the internal logical relationship between the influencing factors through the multi-level hierarchical structure diagram. Finally, through the analysis of the influencing factors of extremely short construction period under the sufficient resources, it defined that the key factor is the natural environment and second is the structure type. The methodology implemented in this paper helps decision makers and managers of construction projects to understand the interrelationship and degree of influence among factors affecting the duration under the condition of sufficient resources, to effectively grasp key factors, and to effectively achieve project success.