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1 – 10 of over 1000Laiming Yu, Yaqin Fu and Yubing Dong
The purpose of this study is to investigate the thermomechanical condition on the shape memory property of Polybutylene adipate-co-terephthalate (PBAT). PBAT is a widely…
Abstract
Purpose
The purpose of this study is to investigate the thermomechanical condition on the shape memory property of Polybutylene adipate-co-terephthalate (PBAT). PBAT is a widely researched and rapidly developed biodegradable copolyester. In a tensile test, we found that the fractured PBAT samples had a heat-driven shape memory effect which piqued our interest, and it will lay a foundation for the application of PBAT in new fields (such as heat shrinkable film).
Design/methodology/approach
The shape memory effect of PBAT and the effect of the thermomechanical condition on its shape memory property were confirmed and systematically investigated by a thermal mechanical analyzer and tensile machine.
Findings
The results showed that the PBAT film had broad shape memory transform temperature and exhibited excellent thermomechanical stability and shape memory properties. The shape memory fixity ratio (Rf) of the PBAT films was increased with the prestrain temperature and prestrain, where the highest Rf exceeded 90%. The shape memory recovery ratio (Rr) of the PBAT films was increased with the shape memory recovery temperature and decreased with the prestrain value, and the highest Rr was almost 100%. Moreover, the PBAT films had high shape memory recovery stress which increased with the prestrain value and decreased with the prestrain temperature, and the highest shape memory recovery stress can reach 7.73 MPa.
Research limitations/implications
The results showed that PBAT had a broad shape memory transform temperature, exhibited excellent thermomechanical stability and shape memory performance, especially for the sample programmed at high temperature and had a larger prestrian, which will provide a reference for the design, processing and application of PBAT-based heat shrinkable film and smart materials.
Originality/value
This study confirmed and systematically investigated the shape memory effect of PBAT and the effect of the thermomechanical condition on the shape memory property of PBAT.
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Kunal Arora, Mohit Kumar and Varun Sharma
The paper aims to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. Shape memory polymers are a promising family of materials for biomedical…
Abstract
Purpose
The paper aims to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. Shape memory polymers are a promising family of materials for biomedical applications because of their favourable mechanical properties, fast reactions and good biocompatibility. For most SMPs, however, achieving controllable sequential shape change is challenging.
Design/methodology/approach
In the present work, 4D printing technology is used to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. A comparative study of pure PLA and graphite’s different weight % composition has been done.
Findings
By carefully managing the deformation state, PLA with graphite shape memory composites produced controllable sequential deformation with an amazing shape memory effect. Surface morphology, thermal properties, melt flow index and shape recovery tests have all been carried out to assess the qualities of manufactured samples.
Originality/value
This is a one-of-a-kind to fabricate shape memory composites using graphite and a PLA matrix. Thus, this research attempts to deliver the possible use of PLA/graphite composites fabricated using 4D printing in robotics and biomedical devices.
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Fukang Yang, Wenjun Wang, Yongjie Yan and YuBing Dong
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to…
Abstract
Purpose
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to improve the thermal insulation performance of polyethylene terephthalate (PET), the SiO2 aerogel/PET composites slices and fibers were prepared, and the effects of the SiO2 aerogel on the morphology, structure, crystallization property and thermal conductivity of the SiO2 aerogel/PET composites slices and their fibers were systematically investigated.
Design/methodology/approach
The mass ratio of purified terephthalic acid and ethylene glycol was selected as 1:1.5, which was premixed with Sb2O3 and the corresponding mass of SiO2 aerogel, and SiO2 aerogel/PET composites were prepared by direct esterification and in-situ polymerization. The SiO2 aerogel/PET composite fibers were prepared by melt-spinning method.
Findings
The results showed that the SiO2 aerogel was uniformly dispersed in the PET matrix. The thermal insulation coefficient of PET was significantly reduced by the addition of SiO2 aerogel, and the thermal conductivity of the 1.0 Wt.% SiO2 aerogel/PET composites was reduced by 75.74 mW/(m · K) compared to the pure PET. The thermal conductivity of the 0.8 Wt.% SiO2 aerogel/PET composite fiber was reduced by 46.06% compared to the pure PET fiber. The crystallinity and flame-retardant coefficient of the SiO2 aerogel/PET composite fibers showed an increasing trend with the addition of SiO2 aerogel.
Research limitations/implications
The SiO2 aerogel/PET composite slices and their fibers have good thermal insulation properties and exhibit good potential for application in the field of thermal insulation, such as warm clothes. In today’s society where the energy crisis is becoming increasingly serious, improving the thermal insulation performance of PET to reduce energy loss will be of great significance to alleviate the energy crisis.
Originality/value
In this study, SiO2 aerogel/PET composite slices and their fibers were prepared by an in situ polymerization process, which solved the problem of difficult dispersion of nanoparticles in the matrix and the thermal conductivity of PET significantly reduced.
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This paper aims to investigate the effects on coatings performance in the epoxy silicone resin system owing to the existence of the different chain length of open-chain epoxy…
Abstract
Purpose
This paper aims to investigate the effects on coatings performance in the epoxy silicone resin system owing to the existence of the different chain length of open-chain epoxy monomer. In this paper, [4-Methylphenyl-(4–(2-methylpropyl) phenyl)]iodonium as photoinitiator was added into epoxy silicone resin by ultraviolet (UV)-cured polymerization to investigate the effects on coatings performance owing to the existence of the different chain length of open-chain epoxy monomer.
Design/methodology/approach
A simple hydrosilylation reaction was used to synthesize epoxy-based silicone prepolymers by using hydrogen-terminated polydimethylsiloxane, 1,2-epoxy-5-hexene, 1,2-epoxy-7-octene and 1,2-epoxy-9-decene as precursors.
Findings
The results revealed that the glass transition temperatures (Tg) and hydrophobicity increased with the chain length of open-chain epoxy monomer in the UV curable epoxy-based silicone coatings, and these films had excellent heat resistance, hydrophobicity, antigraffiti and ink removal properties.
Research limitations/implications
The cationic photocuring systems are not susceptible to the effect of oxygen inhibition. However, the limitation of cationic light curing process is that it requires a long curing time.
Originality/value
The coatings prepared via the UV curing approach can provide superior antismudge effects, and thus they are promising candidates for use in various industries, especially in fields such as antismudge coatings and antigraffiti coatings.
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Laiming Yu, Yaqin Fu and Yubing Dong
The purpose of this study is to improve the mechanical property and processing performance and reduce the cost of the polylacticacid/polybutyleneadipate-co-terephthalate(PLA/PBAT…
Abstract
Purpose
The purpose of this study is to improve the mechanical property and processing performance and reduce the cost of the polylacticacid/polybutyleneadipate-co-terephthalate(PLA/PBAT) composites, the calcium carbonate (CaCO3) and compatibilizer styrene-maleicanhydride copolymer (SMA-2025) were added to the PLA/PBAT system, and the effect of CaCO3 and SMA-2025 on the morphology, structure, mechanical property, thermal property, thermalstability and shape memory property of the CaCO3/PLA/PBAT composites were studied and discussed.
Design/methodology/approach
The CaCO3/PLA/PBAT shape memory composites were prepared via melt-blending and hot-pressing methods, and the effect of CaCO3 and SMA-2025 on the property of the composites was investigated via scanning electron microscope, universal testing instrument, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis and DMA, respectively.
Findings
The interface property, mechanical property, thermal stability, shape memory recovery ratios and recovery stresses, and processing performance of the CaCO3/PLA/PBAT shape memory composites were significantly improved by adding of CaCO3 and SMA-2025. Moreover, the CaCO3/PLA/PBAT composites have good blowing film processing performance.
Originality/value
This study will provide a reference for the research, processing and application of the high-performance CaCO3/PLA/PBAT shape memory composites.
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Noel Scott, Brent Moyle, Ana Cláudia Campos, Liubov Skavronskaya and Biqiang Liu
Research on the impact of the engagement of online medical teams (OMTs) on patient evaluation, for example, satisfaction, remains insufficient. This study attempts to recognize…
Abstract
Purpose
Research on the impact of the engagement of online medical teams (OMTs) on patient evaluation, for example, satisfaction, remains insufficient. This study attempts to recognize the underlying mechanism of how OMTs’ engagement influences patient satisfaction by adopting social support as the mediator. This study also scrutinizes the moderating effects of the transactive memory system (TMS) on the link between OMTs’ engagement and social support.
Design/methodology/approach
We utilized a linear model that had fixed effects controlled at the team level for analysis. A bootstrapping approach using 5,000 samples was employed to test the mediation effect.
Findings
Our results reveal that OMTs’ engagement improves informational and emotional support, thereby promoting patient satisfaction. Specialization and credibility strengthen the impact of OMTs’ engagement on informational and emotional support. Simultaneously, coordination has an insignificant influence on the link between OMTs’ engagement and social support.
Originality/value
This study contributes to the literature on OMTs, social support, and TMS, providing insights into patients’ perceptions of OMTs’ engagement during online team consultation. This study also generates several implications for the practice of online health communities and OMTs.
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The purpose of this study aims to synthesize a novel donor–acceptor dye based on phenothiazine as a donor (D) and nonconjugated spacer was devised and synthesized by condensing of…
Abstract
Purpose
The purpose of this study aims to synthesize a novel donor–acceptor dye based on phenothiazine as a donor (D) and nonconjugated spacer was devised and synthesized by condensing of 2,2'-(1H-indene-1,3(2H)-diylidene) dimalononitrile with aldehyde and the practical synthesis methodology as given in Scheme 1.
Design/methodology/approach
The prepared phenothiazine dye was systematically experimentally and theoretically examined and characterized using nuclear magnetic resonance spectroscopy (1H,13C NMR), Fourier-transform infrared spectroscopy (IR) and high-resolution mass spectrometry. Density functional theory (DFT) and time-dependent density functional theory DT-DFT calculations were implemented to determine the electronic properties of the new dye
Findings
The UV-Vis absorption and fluorescence spectroscopy of the synthesized dye was investigated in a variety of solvents with varying polarities to demonstrate positive solvatochromism correlated with intramolecular charge transfer (ICT). The probe’s quantum yields (Фf) are experimentally measured in ethanol, and the Stokes shifts are found to be in the 4846–9430 cm−1 range.
Originality/value
The findings depicted that the novel (D-π-A) chromophores may act as a significant factor in the organic optoelectronics.
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Thi Thanh Thao Nguyen and Thi Dung Hanh Duong
Previous studies have proven the significant influence of nostalgia on tourists' perceptions, intentions, and behaviors. While much of the research has focused on nostalgia as a…
Abstract
Purpose
Previous studies have proven the significant influence of nostalgia on tourists' perceptions, intentions, and behaviors. While much of the research has focused on nostalgia as a motivator for destination choice in the pre-trip stage, fewer studies have explored the effects of nostalgia experienced during visits on other behavioral intentions beyond revisit intention. This paper aims to fill this gap by examining the impact of nostalgic emotion experienced at tourist destinations on behavioral intentions, specifically pro-sustainable behavioral and word-of-mouth (WOM) intentions through destination image.
Design/methodology/approach
This study developed a conceptual model grounded in existing literature and empirical research on nostalgia and consumer behavior. Data were gathered from international tourists via surveys conducted in Hue City, a UNESCO World Heritage Site. The hypotheses were tested using structural equation modeling (SEM) with Amos 23.0.
Findings
The research results reveal that nostalgic emotion positively impacts destination image and WOM intention. Destination image correlates positively with both pro-sustainable behavioral intention and WOM intention. Destination image serves as a mediator in the relationship between nostalgic emotion and WOM intention. Theoretical and practical implications are also discussed in the current work.
Practical implications
The findings of this research provide guidance for nostalgic elements to be integrated into tourism experiences and marketing campaigns to enhance tourists' emotional connections, thereby improving the destination’s overall appeal. Additionally, while nostalgia does not directly foster pro-sustainable behavioral intentions, a positive destination image can influence these behaviors, suggesting that sustainable tourism strategies should also focus on strengthening the destination’s image.
Originality/value
This paper contributes to both theoretical advancements and practical applications in the field of tourism psychology and marketing by shifting the focus from nostalgia as a motivator for destination choice in the pre-trip stage to exploring the effects of nostalgic emotions experienced during visits on behavioral intentions beyond revisit intentions.
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War is one of the worst characteristics of human nature. Wars over territory, religion, and governance were and are always present through history. War and tourism seem dissonant…
Abstract
War is one of the worst characteristics of human nature. Wars over territory, religion, and governance were and are always present through history. War and tourism seem dissonant at first glance. However, the post effects of war enable its components, such as battlefields and artefacts, to become tourist attractions. People share the impetus to visit war attractions such as battlefields, military museums, cemeteries, memorials, and other war-related sites. There is a supply for this type of tourism in exchange for the demand. This type of tourism is referred to in the literature as battlefield tourism. The meaning and definition of battlefield tourism are the main aim of this chapter. What is battlefield tourism? What are the components of battlefield tourism? How can battlefield tourism be defined? These are the primary questions this study tries to address.
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