Applied Sciences-Basel
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2026
·Vol. 16
·期 9
·4152
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IF 2.9
Jianyi Liu,Yang Cao
In the process of extracting and transporting waxy crude oil, pipeline blockages resulting from wax deposition significantly impede production efficiency and lead to substantial economic losses. Ethylene vinyl acetate copolymer (EVA) is a widely used chemical wax inhibitor; however, its performance is influenced by multiple factors, including its molecular structure, concentration, and the carbon number distribution of the wax system. A systematic elucidation of its mechanism of action and associated phase changes is therefore necessary. In this study, differential scanning calorimetry (DSC) was employed to systematically investigate the thermal behavior of a wax system with a broad carbon number distribution (C5–C50). The objectives were to analyze the influence of EVA concentration, vinyl acetate (VA) content, and molecular weight on the phase transition parameters, to elucidate the wax inhibition mechanism, and to construct a phase prediction model based on the Flory–Huggins theory. The results demonstrate that the wax appearance temperature (WAT), phase transition temperature, and phase transition enthalpy of the wax systems increase monotonically with carbon number. Furthermore, the addition of EVA was found to significantly reduce both the WAT and the amount of wax precipitated. The optimal structural parameters were identified as a VA content of 10%, a number average molecular weight of 20,000, and an optimal concentration of 800 ppm. The medium-carbon wax system (C16–C30) was found to be the most sensitive to the EVA response. The established phase model exhibited high predictive accuracy, with a mean relative error of less than 4%, a root mean square error (RMSE) of 0.32%, and a coefficient of determination (R2) of 0.987, thereby providing preliminary insights and a practical tool for optimizing EVA wax inhibitor formulations under simplified conditions and guiding their potential engineering applications.
Keywords: EVA wax inhibitor; differential scanning calorimetry; wax deposition; N-alkanes; phase transition behavior; phase model
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2018
·
IF 1.454
Ziyi Tu,Guolin Jing,Zhengnan Sun,Zhiwei Zhen,Wei Li
Nanocomposites of attapulgite (ATT)/ethylene vinyl acetate copolymer (EVA) were prepared with organically modified ATT covering in EVA. Organically modified ATT was prepared using KH550 and organic acid. The effect of nano-hybrid on the flow behavior of model oil containing 15 wt% wax was evaluated. The wax crystallization and crystal morphology of the model oil at low temperature were observed by polarizing optical microscopy (POM). The results indicated that the nano-hybrid with long-chain organic acid-modified ATT exhibited a better effect compared with the nano-hybrid with short-chain organic acid-modified ATT, pure EVA. In addition, it is interesting to note that EVA (VA = 32%)/stearic acid-modified ATT composite polymeric pour-point depressant (PPD) S-AtPPD(32) provided better cold-flow improvement for the model oil than EVA (VA = 32%)-modified nano-SiO2 composite PPD N-SiPPD (32) with a low dose, which resulted in a regular, bar-shaped, and uniform arrangement of wax morphologies. The pour point of the model oil was reduced from 30°C to −1°C when doped at 200 ppm S-AtPPD(32).
研究领域:
石油工程
·
材料科学
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RSC Advances
·
2019
·Vol. 9
·期 34
·19501-19507
·
IF 3.049
Yuqiu Shen,Zhenxing Chen,Yong Zhou,Zuomin Lei,Yi Liu,Wenchao Feng,Zhuo Zhang,Houfu Chen
Solvent-free electrically conductive composites have been applied to flexible electronics to obtain high electrical conductivity. However, some of the proposed composites have low electrical conductivities and are unable to meet the requirements of commercial printable electronics. In this study, solvent-free electrically conductive Ag/EVA (ethylene vinyl acetate) composites for paper-based printable electronics were prepared by a thermal melting method. The properties of these electrically conductive Ag/EVA composites, including particle sizes, morphologies and phase purities of the flake silver flake powders, were investigated using a particle size analyzer, scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results showed that nanometer-thick flake silver flake powders with smooth and flat surfaces were made by the nanofilm transition technique. These obtained powders were able to form smooth face-to-face contacts, which facilitated the formation of an excellent conductive network in the conductive system. Dynamic mechanical analysis (DMA) was conducted to investigate the mechanical properties of EVA and Ag/EVA composites. A Fourier transformation infra-red (FTIR) spectrometer, laser micro-Raman spectrometer and thermogravimetric analyzer were used to analyze the organic functional groups, glass transition temperatures and thermal weight losses of the EVA resin and solvent-free electrically conductive composites. The solvent-free electrically conductive Ag/EVA composite, which contained 55 wt% of the as-prepared flake silver flake powders, was found to have an extremely low volume resistivity of 1.23 × 10−4 Ω cm as well as excellent bending performance and adhesion. These features indicate the great potential of these composites for application in printed electronics.
研究领域:
材料科学
·
电子工程
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PubMed
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PROGRESS IN ORGANIC COATINGS
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2020
·
IF 4.469
Yixuan Wang,Caixiang Chen,Xia Wu,Zhihui Wang,Shumei Wen,Jing Yu,Chenghu Yan,Wei Cong
Biofouling is a critical challenge for the commercial application of photobioreactors for microalgae cultivation. In this work, a series of amphiphilic sulfobetaine copolymers (ASC) with different ratios of sulfobetaine (SBMA) and 2, 2, 2-trifluoroethyl methacrylate (TFMA) were synthesized via a monomer-starved seeded semi-continous emulsion polymerization method and were used to improve the antibiofouling capability of ethylene-vinyl acetate copolymer (EVA) film by surface coating method. Effects of the SBMA/TFMA ratio on the resultant ASC latexes and coating properties were investigated. With the increase of the SBMA/TFMA ratio, the particle diameter, polydispersity index and water uptake of ASC latexes and coating decreased from 261.8 nm to 144.9 nm, 0.198 to 0.054 and 26.28 % to 7.84 %, respectively, and increased afterwards. Fourier transform Infrared (FT-IR) spectra and X-ray photoelectron spectroscopy analysis (XPS) indicated that SBMA and TFMA were introduced onto the EVA film surface successfully. The contact angle of ASC modified EVA (EVA-ASC) film sharply decreased after immersed in water. The EVA-ASC film either in dry, or in water swollen state exhibited excellent optical transparency in the visible light. The adsorption of bovine serum albumin and Chlorella sp. on the EVA-ASC surface was investigated with protein and microalgae adsorption assay. It was shown that the EVA-ASC film had excellent protein and microalgae absorption resisting characteristic, the density of absorbed protein and microalgae decreased 92 % and 50 % compared with those of EVA film, respectively.
研究领域:
生物技术
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材料科学
·
环境工程
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Frontiers in Materials
·
2022
·
IF 3.985
Long Biyu,Zhou Xianzi,Cao Huafeng,Chen Renjie,He Nannan,Chi Lina,Fan Penghui,Chen Xiaohong
Superior encapsulation technology is important for PSCs to prolong their lifetime and realize their commercial application. Paraffin/EVA/paraffin composite encapsulated layers were fabricated with the ambient environment under the thermal temperature of 80°C, which has advantages for simple procedures and low cost. PSCs encapsulated with paraffin/EVA/paraffin and pure EVA layers maintained 95 and 45% of the initial power conversion efficiency (PCE) aged for 1000 h at RH 75%, respectively. Paraffin/EVA/paraffin-encapsulated PSCs were immersed in water for 5 h, which remained 98% of the original PCE, which is far superior to EVA-encapsulated PSCs. High melting point paraffin at 68°C shows better encapsulation than low melting point (60 and 55°C) paraffin, indicating that the high molecular weight of paraffin helps improve the encapsulation performance of PSCs. PSCs encapsulated with paraffin/EVA/paraffin showed better stability of Voc than pure EVA layer because paraffin can inhibit defects, voids, and edges of metal electrodes that quickly expand, and decay. Therefore, paraffin/EVA/paraffin combination encapsulation is an effective strategy, which can form continuous and dense hydrophobic composite encapsulation films with a friendly metal electrode.
研究领域:
材料科学
·
能源技术
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Functional Materials Letters
·
2026
·
IF 1
Yang Sheng,Xinyu Zhu,Xingyu Liu,Peng Zhang,Yixin Sun,Rong Zhang
Developing novel materials to improve the global food supply is vital to combat hunger, achieve food security and promote sustainable agriculture. To address this issue, we employed red-emitting Ag-In-S-Zn (AISZ) quaternary quantum dots (QDs) as light converters to fabricate AISZ QDs-loaded ethylene vinyl acetate (EVA) copolymers (AISZ/EVA) films to improve the light conditions for crop growth. The synthesis of AISZ QDs was optimized to achieve a high quantum yield (73%) and an emission band matching the absorption window of chlorophyll a and b. Using EVA resin as the matrix, efficient ultraviolet-to-red light-converting AISZ/EVA films with varying AISZ content were prepared by the solvent evaporation method. The fluorescence and transmittance of these light-conversion films along with a blank EVA control, were characterized. Subsequent 28-day lettuce cultivation under controlled light illumination revealed that the 1.0 wt.% AISZ/EVA film induced maximal growth enhancement. The fresh weight and dry weight were increased by 28.2% and 34.4%, respectively, while the contents of total chlorophyll, chlorophyll a, chlorophyll b, carotenoid, soluble sugars and proteins were increased by 48.8%, 51.3%, 43.8%, 40.8%, 33.6% and 37.2%, respectively. The results demonstrate that broad-emitting AISZ QDs served as efficient light converters to fabricate agricultural light-conversion films, highlighting their broad application prospects and promising commercial potential in controlled environment agriculture.
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Surfaces and Interfaces
·
2026
·
IF 6
Linzhuo Liu,Junjun Ma,Jingxian Tang,Jingjing Luo,Qisong Feng,Shilian Wu,Zunxiang Ma,Guijun Zhang,Yu Yang
The utilization of discarded EVA plastic to fabricate superhydrophobic coatings aligns with the principles of sustainable technology and paves a new way for the repurposing of waste EVA. • The coating boasts >98% transmittance and a >155° water contact angle. It exhibits excellent stability under UV, high-temperature, and water impingement conditions, and its short curing time makes it highly promising for practical use. • Incorporating EVA repairs coating defects, reduces porosity, and significantly enhances optical transparency. The withdrawal speed in dip-coating determines the coating thickness: faster speed leads to thicker coating, with optical properties showing clear thickness dependence. Ethylene-vinyl acetate (EVA) copolymers are extensively utilized as encapsulation materials in photovoltaics owing to their excellent adhesion, high transparency, and weathering resistance. However, efficient recycling pathways for the strip-shaped waste generated during industrial-scale manufacturing remain limited. Herein, we devised a novel recycling strategy to fabricate a highly transparent and superhydrophobic self-cleaning coating by incorporating waste EVA and hexamethyldisilazane (HMDS)-modified SiO₂ nanoparticles via a simple dip-coating process. The resultant coating exhibited outstanding superhydrophobicity, with a water contact angle exceeding 155° and a sliding angle below 2°, while maintaining exceptional visible-light transmittance of over 98%. Systematic microstructural analyses revealed that the quantity and size distribution of defects, along with the film thickness, were the primary factors governing optical performance, whereas surface roughness played a comparatively minor role. The coating thickness could be precisely controlled by adjusting the lift speed during dip-coating, and complete curing was achieved within 2 min. This work not only provides an effective recycling pathway for waste EVA but also demonstrates considerable potential for applications requiring both high transparency and self-cleaning functionality, such as solar panel covers and architectural glazing. Download: Download high-res image (207KB) Download: Download full-size image
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ACS Omega
·
2025
·
IF 4.3
Jiajun Ren,Liuqi Liu,Guowei Wang,Xiaofen Chen,Ruiqiang Chen,Lixin Wu,Longhui Zheng
During the supercritical foaming process, regulation of the foaming behavior is an extremely challenging issue. In this study, polycaprolactone/ethylene vinyl acetate copolymer (PCL/EVA) blends were prepared by mechanical mixing and further foamed by supercritical nitrogen foaming. The precise control of the phase structure of the material was achieved through the adjustment of the blend components, and the mechanisms behind the foaming behavior were further revealed. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and mechanical properties were used to investigate the effect of the blend phase structure on the structure and properties of the foams. The results show that the PCL/EVA blend exhibits a sea–island structure with gradually increasing phase sizes at low PCL content (10–30 wt %). Upon increasing the PCL content to 40 wt %, the phase size further increases, tending to form a bicontinuous structure. With the increase of PCL addition, the expansion ratio of the foams was increased from 7.98 to 11.96, the vesicle density was increased from 1.36 × 107 to 4.05 × 107 cells/cm3, and the average cell size was decreased from 66.12 ± 16.35 to 46.44 ± 11.76 μm. The introduction of PCL into the EVA yielded foams with denser cells and a softer texture, which improved the compression permanent deformation (from 2.53 to 0.59%) and the compression resilience (from 95.5 to 96.93%) of the foams. This work provided a new avenue for regulating the foaming behavior of blends and the development of lightweight and high performances for foams.
研究领域:
材料科学
·
高分子化学
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PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2012
·
IF 2.237
Yan Liu,Yan Zhang2,Zhenhu Cao,Zhengping Fang
Three novel intumescent flame retardants (IFRs), polyphosphate esters (designated as PDP, PEP, and PPP), were synthesized by reacting phenyl dichlorophosphate with three bis-hydroxy azomethine monomers through interfacial polycondensation. The polyphosphate esters were characterized by hydrogen nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Thermal stability and flammability properties of ethylene vinyl acetate copolymer (EVA)/30%IFRs blends were investigated by thermogravimetric analysis (TGA), limited oxygen index (LOI), and microscale combustion calorimeter (MCC). The EVA/IFRs blends exhibited high thermal stabilities, and char yields at 600 °C were 11–19% in nitrogen. The results from MCC indicated that the addition of PPP to EVA reduced the PHRR by about 33%, while the LOI values increased from 19 to 22. Scanning electron microscope (SEM) observation results indicated that the existence of the tight charred layer on the surface of the residues was responsible for the improvement of the flame retardancy of EVA.
研究领域:
材料科学
·
高分子化学
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Xinyue Wang,Xiangxia Zhang,Dong Xiang,Zhuxi Liu,Libing Liu,Chunxia Zhao,Hui Li,Menghan Wang,Bin Wang,Yuanpeng Wu
Developing flexible and wearable strain sensors that combine high performance and cost-effectiveness remains a challenge. In this work, a carbon nanotube/styrene–butadiene–styrene/ethylene vinyl acetate copolymer (CNT–SBS/EVA) flexible strain sensor with a double percolation structure was prepared by melt mixing and biaxial stretching at different stretching ratios (SRs). As the SR increased, the dispersion and orientation of the CNTs were further improved. Compared with the unstretched 2 wt.% CNT–SBS/EVA-1.0 sample (strain range 100%, gauge factor (GF) = 1237.95), the mechanical properties, sensitivity, and strain detection range were significantly improved after biaxial stretching. The elongation at break of the 2 wt.% CNT–SBS/EVA-1.5 (biaxially stretched at a SR of 1.5) sample increased by 310%. It exhibited higher sensitivity (GF = 176480.58), good linearity ( R 2 = 0.95) and a wider strain detection range (200%), as well as superior sensing performance and durability (2000 cycles), achieving improved performances. Finally, the practical value and potential applications of the CNT–SBS/EVA sensor in the monitoring of human physiological signals were demonstrated through response tests of different strain levels, such as joint and muscle movements.
研究领域:
材料科学
·
纳米技术
·
传感器
·
高分子科学
·
生物医学工程
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高影响因子
Pigment & Resin Technology
·
2025
·
IF 1.5
Xiaojian Jiang,Zhonggui Zhang,Jiafei Cheng,Yongjie Ai,Ziyue Zhang,Shuolei Wang,Shi Xu,Hongyu Gao,Yubing Dong
Purpose This study aims to fabricate the reduced graphene oxide (rGO)/ethylene vinyl acetate copolymer (EVA) composite films with electric-driven two-way shape memory properties for deployable structures application. The effect of dicumyl peroxide (DCP) and rGO on the structure and properties of the rGO/EVA composite films were systematically investigated. Design/methodology/approach The rGO/EVA composite films were fabricated by melting blend and swelling-ultrasonication method, DCP and rGO were used the crosslinking agent and conductive filler, respectively. Findings The research results indicate that the two-way shape memory properties of rGO/EVA composite films were significantly improved with the increase of DCP content. The rGO endowed rGO/EVA composite films with excellent electric-driven reversible two-way shape memory and anti-ultraviolet aging properties. The sample rGO/EVA-9 can be heated above Tm within 8 s at a voltage of 35 V and can be heated above the Tm temperature within 12 s under near-infrared light (NIR). Under a constant stress of 0.07 MPa, the reversible strain of the sample rGO/EVA-9 was 8.96% and its electric-driven shape memory behavior maintained great regularity and stability. Research limitations/implications The rGO/EVA composite films have potential application value in the field of deployable structures. Originality/value With the increase of DCP content, the two-way shape memory properties of rGO/EVA composite films were significantly improved, which effectively solved the problem that the shape memory properties of EVA matrix decreased caused by swelling. The rGO endowed rGO/EVA composite films with excellent electric/NIR driven reversible two-way shape memory properties.
研究领域:
材料科学
·
智能材料
·
高分子化学
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高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2026
·
IF 3.2
Haohao Hou,Linqi Lu,Hui Ma,Hongfu Zhou,Xiangdong Wang,Munan Qiu,Xiaoling Zang
The rapid development of 5th generation communication and wearable electronic devices has increased the demand for lightweight and flexible materials with excellent electromagnetic interference (EMI) shielding performance and piezoresistive sensing characteristics. Herein, cold/hot pressing was combined with supercritical CO 2 foaming to prepare segregated carbon nanotube (CNT)/ethylene-vinyl acetate copolymer (EVA)/low-density polyethylene (LDPE) sheets and related foams, exhibiting superior sensitivity and EMI shielding effectiveness (SE). Benefiting from the segregated distribution of CNT, CNT/EVA/LDPE sheets exhibited excellent conductivity of 0.38 S cm −1 . The composite foam with 6 phr CNT achieved a maximum absolute EMI SE of 113 dB (g/cm 2 ) −1 in the X-band (8.2–12.4 GHz) while maintaining high sensitivity (GF = 4.4), perfectly balancing piezoresistive sensing and EMI shielding performance. Apart from pure EVA/LDPE, the mechanism for EMI shielding in CNT/EVA/LDPE sheets was primarily based on reflection, while that of segregated CNT/EVA/LDPE foam was chiefly ascribed to absorption. Moreover, the segregated CNT/EVA/LDPE foam could accurately detect human motion, further demonstrating their practical application potential. This study provides new insights into the development of lightweight, multifunctional materials for EMI shielding and advances next-generation functional materials for flexible electronics and wearable devices. Highlights A composite that integrates mechanical, conductive, EMI shielding and sensing. S/C6-F shows excellent conductivity (0.01 S cm −1 ) and SSE/t (113 dB cm 2 g −1 ). Its porous structure shifts EMI shielding from reflection to absorption. A high gauge factor of 4.4 enables S/C6-F to accurately detect human motion. S/C6-F achieves 7 MPa stress at 60% strain, indicating mechanical stability.
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