Epoxy resin-based composites have an important and extensive application value in both military and civilian, but their poor fire safety hinders their further development. Therefore, it is very ...important to improve the flame retardant properties of epoxy resin matrix composites, and a large number of literature reports have appeared in recent years. Biogenic epoxy resin flame retardants have emerged as the times require due to the problems of large amount of addition, difficult dispersion and low interfacial strength of epoxy resin flame retardants, as well as the continuous improvement of people's awareness of green chemistry and sustainable development. In this review, scholars will realize the necessity of flame retardant epoxy resin, understand the burning process, type of flame retardants and flame retardant mechanism of epoxy resin. Mastering the preparation method of epoxy resin flame retardants related to the two most popular biogenic materials, phytic acid (PA) and chitosan (CS), and the influence on the performance of epoxy resin matrix and the flame retardant mechanism. Discovering the advantages, challenges and prospects of biogenic materials PA and CS in the research of flame retardant properties of epoxy resins.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The poor interfacial adhesion between silicone rubber and polyethylene glycol terephthalate (PET) affects the safety and durability of fabric-rubber products in service. In this study, a low-cost and ...simple atmospheric plasma surface treatment device is used to treat the surface of polyester fabric continuously, followed by coating KH570 onto the fabric surface. The adhesion strength of fabric-rubber interface is successfully enhanced by this method. The peel strength of the specimens treated with this bonding process reaches 3.92 N/mm and 5.73 N/mm in the warp and weft directions, respectively, which are 5.16 and 7.44 times of untreated fabric samples, superior to commercially-available silicone rubber adhesive. In addition, the bonding mechanism of the interface is characterized by Fourier transform infrared spectra (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and water contact angle test. This study provides a practical and environmentally friendly method for fabricating fabric silicone rubber materials with high interfacial performances.
Display omitted
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Direct ink writing of soft materials is a very promising technology in 3D printing, and the rheological properties of inks are crucial for successful printing. In this paper, the effect of the ...rheological properties on the printing process of silicone rubber inks is studied to lay a foundation for the configurations of 3D printing process parameters. Also, the shape retention of the printing filaments is studied to provide a basis for the viscosity deployment of the inks. In addition, by studying the die swell ratio of nano‐silica‐reinforced silicone rubber inks at normal printing speed, it is found that the die‐swell ratio is proportional to the ink's relaxation time. Finally, the influence of the configuration of the short‐nozzle on the die swell is investigated, and the concave nozzle has a smaller extrusion swelling effect than the convex nozzle and the conical nozzle, providing new ideas for the adjustment of the filament diameter.
Direct ink writing of soft materials is a very promising technology in 3D printing, and the rheological properties of inks are crucial for successful printing. However, the extrusion swelling of inks will greatly affect the accuracy of printing. By changing the configuration of the nozzle, the influence of the swelling effect of the ink on the diameter of the printing filament can be adjusted.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, based on phytic acid (PA), chitosan (CS) and tetrapod zinc oxide (TZ), a biobased flame retardant material (TZ@PA@CS) was synthesized by solution self-assembly method. A halogen-free ...green intumescent epoxy resin (EP) flame retardant system was composed of TZ@PA@CS and melamine cyanurate (MCA), and its thermal stability, flame retardancy, mechanical properties and related mechanism were studied in detail. The results show that the thermal stability of EP composites is improved after adding 3 wt% TZ@PA@CS and 5 wt% MCA into EP, and it can easily pass the UL-94 V-1 grade. At the same time, compared with pure EP, its peak heat release rate decreased by 44%, and the char residue rate increased by about 100% in cone calorimeter test. It is found that TZ@PA@CS and MCA have outstanding grading and synergistic flame retardant effects, and can form a dense, expansive and phosphorus-containing char layer. Besides, its impact and compression strength and compression deformation are increased by 41%, 39% and 155% respectively, which shows that it has good energy absorption, impact toughness and compression strength. This work provides a simple strategy for preparing biobased EP composites with excellent flame retardant properties, impact resistance and compression resistance.
Display omitted
•A novel biobased green flame retardant was synthesized.•The prepared flame retardant exhibited excellent synergistic effects with melamine cyanurate.•The flame-retardant properties and mechanisms of tetra-needle zinc oxide have been studied in detail for the first time.•The thermal stability, flame retardancy, and mechanical properties of epoxy resin can be significantly improved.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The wear resistance and tear strength of silicone rubber can be greatly improved by warp knitted polyester fabric, but the application of fabric rubber composites is limited by the poor bonding ...interface between the fabric and the rubber. In this study, the fabric is immersed in an alkaline solution first and a coupling agent in sequence with ultrasonic treatment. Then, fabric rubber composites with high bonding strength between fabric and rubber are prepared through a co-vulcanization process. The adhesion mechanism between the fabric and the rubber is analyzed through Fourier transform infrared spectra (FT-IR), Raman spectrum, contact angle test and peel test. The adhesion strengths of samples treated by KH570 along warp and weft direction of fabric reach 8.0 N·mm-1 and 4.82 N·mm-1, respectively, which are 10.35 times and 5.91 times higher than those of original fabric samples. This greatly improves the delamination resistance of fabric rubber composites under large strain and expands its application range.
Display omitted
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, low density hollow glass beads (HGB)/silicon rubber (SR) composites were prepared by solution method and flocculation process. The prepared samples were characterized by scanning ...electron microscopy, Fourier transform infrared spectroscopy, tensile test, and friction test. The results show that the densities of SR composites decrease from 1.140 to 0.792 g/cm3 with the addition of HGB. By comparing theoretical density with true density, it can be estimated that the ratio of shattered HGB increase from 8.79% to 24.76%. Especially, the mechanical properties of SR composites were improved by surface modification of HGB. By adding surface‐modified HGB at 5 and 10 wt%, the tensile strengths of SR composites were enhanced by 17.8% and 28.2%, respectively. In addition, tear strength, shore A hardness, compression set, and friction property were significantly ameliorated. Furthermore, the mechanism of surface‐modified HGB in mechanical properties was analyzed.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•A precise vulcanization equation was developed over a broader temperature range.•A finite element model for heat vulcanizing bonding of seals was established.•The effects of the vulcanization ...parameters on residual stress were revealed.•The residual stress of seal joints was reduced by optimizing the heating process.
Vulcanization has a great impact on the performance of rubber products, which is difficult to analyze due to its complicated process and boundary conditions, especially for complex rubber products like aircraft fabric rubber seals. In this paper, an optimized relationship between reaction order and temperature was first developed based on the comparative study of the existing vulcanization kinetic equations, showing improved accuracy and wider applicable temperature ranges. In the temperature range of 160 °C ∼ 190 °C, the determination coefficient of the model can reach 0.9973. Then, finite element models of pure rubber and fabric rubber were established with Abaqus UMATHT and UMAT subroutines to simulate the vulcanization process and analyze the relationship between the stress in the vulcanization process and the non-uniformity of the vulcanization degree field. Finally, the process of mold core synchronous heating was adopted to reduce the non-uniformity of the vulcanization degree field for the heat vulcanizing bonding joint, so as to reduce the residual stress at the joint. Compared with the traditional upper and lower surface heating mode, the residual stress is reduced by about 20 %. This study provides a theoretical guidance for improving the quality of heat vulcanizing bonding joints of seals.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dry/wet environment's effects on the sliding friction properties of fabric–silicone rubber composites are studied, and the wear resistance of polyester fabric is evaluated. The yarn directions of ...the fabrics (inner and outer) have significant influence on the coefficient of friction (COF) of fabric–silicone rubber composites during sliding friction due to the difference in fabric texture and yarn modulus. The COF's variation laws of fabric–silicone rubber composites under different vertical loads and sliding rates are observed, respectively. Additionally, the outer fabric is more sensitive to the changes of vertical loads than those of the sliding rates under the wet environment, which can be attributed to the destruction of the fabric original structure by high load, resulting in the fabric fibers' pulling and breaking during the steel ball's sliding. This study provides new ideas for the design of fabric–silicone rubber composites applied in friction conditions and complex environments.
Friction morphology of fabric–silicone rubber composites under dry/wet sliding environment.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The effects of titanate on the mechanical properties of silicone rubber and peel strength of polyester fabric with silicone rubber are studied. The tests show that the hardness and mechanical ...properties of silicone rubber containing 0.2 phr titanate are similar to those of pure silicone rubber, and the peel strength (1.11 N/mm) between fabric and rubber matrix without inner fabric is the highest in the test groups. Fourier transform infrared spectra (FT‐IR) and contact angle test indicate that the surface wettability of silicone rubber is effectively enhanced with the addition of titanate, which is a key factor to improve the bonding properties between silicone rubber and polyester fabric because of the more adequate contact between the adhesive and silicone rubber surface. Due to the difference in the modulus of the fabric along different yarn directions, the peel direction has a significant effect on the peel force between the outer fabric and silicone rubber.
Modification of surface wettability of silicone rubber by titanate
Titanate modified silicone rubber helped to enhance the surface wettability of silicone rubber matrix, which can increase the contact area between the adhesive and silicone rubber, and improve the bonding performance between fabric and silicone rubber.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, we report on the fabrication of highly interconnected porous poly(butyl acrylate-
-stearyl methacrylate-
-styrene-
-divinylbenzene) (P(BA-SMA-St-DVB)) monoliths and microbeads
the ...polymerization of high internal phase emulsions (HIPEs) and double emulsions by using a 75% to 85% internal water phase. The morphology and specific surface area were characterized with scanning electron microscopy (SEM) and nitrogen adsorption/desorption measurements, respectively. The oil absorbency, including oil absorption, oil absorption rate and oil retention ratio of as-prepared resins (both monoliths and microbeads), was studied by using kerosene and carbon tetrachloride as analogues of oil pollutants. Thermoanalysis was also carried out to analyze the oil absorption mechanism. The results showed that the resin had a good oil absorption efficiency of aliphatic hydrocarbon and chlorohydrocarbon. The best mass-based absorption capacity of the microbeads towards kerosene and carbon tetrachloride is 8.52 and 20.82 times its own weight, respectively, which is higher than those of the corresponding polyHIPE monoliths. Meanwhile, these microbeads of average 320 microns in diameter have good thermal stability and can be easily collected and recycled by a simple filtration washing method.
Full text
Available for:
IJS, KILJ, NUK, UL, UM, UPUK
PDF