Effect of Different Kinds of CaSO4 Whisker on the Bending Strength and Hygroscopicity of Gypsum Board

2014 ◽  
Vol 638-640 ◽  
pp. 1322-1325 ◽  
Author(s):  
Chang Chen ◽  
Yu Bin Wang ◽  
Hua Wang ◽  
Qian Qian Deng ◽  
Lei Du ◽  
...  

Different kinds of hemihydrate calcium sulfate whiskers were fabricated by calcination method under the condition of 115-600 °C. And the density, moisture rate and mechanical properties of composites of gypsum and whisker were studied. The specific strength of composites was investigated. The results show that gypsum boards with whisker calcined at 115 °C and 300 °C have the maximum and minimum densities, which are about 1658 kg/m3 and 1604 kg/m3, respectively. Hydration ability of anhydrous calcium sulfate whisker is the strongest. The values of specific strength of gypsum board reinforced by different types of whiskers suggested that the porosity of the composites changed with the different kinds of whiskers, which agreed well with the moisture rate and mechanical properties.

2022 ◽  
Vol 2160 (1) ◽  
pp. 012004
Author(s):  
Runmeng Qiao ◽  
Zhengping Zhong ◽  
Qiao Liu ◽  
Jialei Liu ◽  
Wenqing He

Abstract Calcium sulfate whisker (CSW) is a kind of fiber crystal material with high orientation structure. The major goal of this research is to study the changes of mechanical properties and light transmittance of PE greenhouse film with different proportions of CSW. The experimental results show that the mechanical properties and light transmittance of PE/CSW films are enhanced compared with the pure PE. For PE/2%CSW, it shows a 18.6% increase in tear strength, a 3.1% increase in luminous transmittance and 17.7% increase in haze. The PE/5%CSW demonstrates a 12.8% higher in tensile strength, a 20.5% higher in tear strength, a 23.9% lower in luminous transmittance and a 53.0% higher in haze. This article gives a new formula to strengthen the mechanical properties of PE greenhouse films and finds the direction for the research and development of astigmatic covering film.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yongkun Wang ◽  
Yuting Zhang ◽  
Jinhua Zhang ◽  
Junjue Ye ◽  
Wenchao Tian

Purpose The purpose of this paper is to study the influence of calcium sulfate whiskers (CSWs) on the thermodynamic properties and shape memory properties of epoxy/cyanate ester shape memory composites. Design/methodology/approach To improve the mechanical properties of shape memory cyanate ester (CE)/epoxy polymer (EP) resin, high performance CSWs were used to reinforce the thermo-induced shape memory CE/EP composites and the shape memory CSW/CE/EP composites were prepared by molding. The effect of CSW on the mechanical properties and shape memory behavior of shape memory CE/EP composites was investigated. Findings After CSW filled the shape memory CE/EP composites, the bending strength of the composites is greatly improved. When the content of CSW is 5 Wt.%, the bending strength of the composite is 107 MPa and the bending strength is increased by 29 per cent compared with bulk CE/EP resin. The glass transition temperature and storage modulus of the composites were improved in CE/EP resin curing system. However, when the content of CSW is more than 10 Wt.%, clusters are easily formed between whiskers and the voids between whiskers and matrix increase, which will lead to the decrease of mechanical properties of composites. The results of shape memory test show that the shape memory recovery time of the composites decreases with the decrease of CSW content at the same temperature. In addition, the shape recovery ratio of the composites decreased slightly with the increase of the number of thermo-induced shape memory cycles. Research limitations/implications A simple way for fabricating thermo-activated SMP composites has been developed by using CSW. Originality/value The outcome of this study will help to fabricate the SMP composites with high mechanical properties and the shape memory CSW/CE/EP composites are expected to be used in space deployable structures.


2010 ◽  
Vol 152-153 ◽  
pp. 821-824
Author(s):  
Hong Bo Liu ◽  
Ji Hu Wang ◽  
Shao Guo Wen ◽  
Chen Yu

The styrene-acrylic emulsions were prepared by copolymerization of styrene, acrylic acid and n-butyl acrylate; coatings were achieved by adding calcium sulfate whiskers and titanium dioxides at the presence of dispersing agents and rheological additives. The physical and mechanical properties as well as contact angles of coating films formed on tinplate were characterized in detail. The pencil hardness was slightly decreased; the contact angle was greatly decreased from 69.8o to 12oby adding the calcium sulfate to indicate the hydrophilic coating films may have self-cleaning properties.


RSC Advances ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 452-461
Author(s):  
Yi Han ◽  
Xian Zhou ◽  
Li Lei ◽  
Huiqun Sun ◽  
Zhiyuan Niu ◽  
...  

In order to improve the utilization of nanoscale zero-valent iron (nZVI) in activating persulfate (PS), a composite material of nZVI/CSW with nZVI supported on calcium sulfate whiskers (CSWs) was synthesized in this study.


2019 ◽  
Vol 958 ◽  
pp. 53-56
Author(s):  
Aoliabe Pedro da Silva ◽  
Laudir de Castro Ferreira Neto ◽  
Nelson Cárdenas Olivier ◽  
Alessandra Félix da Costa Pereira ◽  
Alan Christie da Silva Dantas

Calcium sulfate dehydrate β (CaSO4. 0,5H2O) is a material obtained from the calcination of gypsite (CaSO4.2H2O). This is a low cost ceramic material very used in building industry. The improvement of their applications is of fundamental technological interest. Polymers are an interesting alternative of reinforcement. Polyvinyl acetate (PVAc) is an addition polymer obtained by the polymerization of vinyl acetate. This polymer is well known to achieve good adhesion to cellulosic surfaces. The aim of this work was to evaluate the mechanical properties of porous plaster bodies reinforced with PVAc. Mechanical behavior was characterized by compression and bending strength. Three water / gypsum ratios: 0.5 0.6 and 0.7 were used on this work. An amount of 5% and 10% PVAc promoted increase on the mechanical properties of gypsum. Higher amounts polymer promoted further decrease of the mechanical properties.


2020 ◽  
Vol 1006 ◽  
pp. 227-232
Author(s):  
Yuliya Danchenko ◽  
Artem Kariev ◽  
Vladimir Lebedev ◽  
Elena Barabash ◽  
Tatyana Obizhenko

The physic-mechanical properties of filled composites based on secondary polypropylene are investigated. As fillers the dispersed wastes of processing of agricultural plants - buckwheat and oat husk, as well as needles flour and wood flour were used. Water absorption, abrasion, impact strength and bending strength of composites were investigated. It has been proven that oat and buckwheat husks can be effectively used in composites based on secondary polypropylene and replace traditional wood fillers. It has been shown that the physic-chemical properties of the filled composites depend on the structure and physicochemical interactions on the phase separation surface, as well as on the surface properties of the filler particles. It is established that for the production of filled composites with improved physic-mechanical characteristics it is necessary to use fillers with small specific surface and concentration of surface functional groups, and the acid-base characteristic of the surface should be closer to neutral. It is shown that these conditions provide for the formation of a uniform structure of the filled composite with less internal stresses.


2013 ◽  
Vol 13 (2) ◽  
pp. 103-108 ◽  
Author(s):  
Sharmila Pradhan ◽  
Ralf Lach ◽  
Wolfgang Grellmann ◽  
Rameshwar Adhikari

The effect of different types of fillers on morphology and mechanical properties of polymer nanocomposites has been investigated using ethylene-1–octene copolymer (EOC), a polyolefin based elastomer, as matrix and various nanofillers {such as multi-walled carbon nanotubes (MWCNT), layered silicate (LS) and boehmite (OS2)}. The morphological structures were studied by scanning electron microscopy (SEM) while the mechanical properties were characterized by tensile testing and microindentation hardness measurements. It has been shown that the nature of the nanofiller may have significant influence on the mechanical properties of the samples. Among the nanocomposites studied so far, the MWCNT filled samples showed the highest reinforcing effect followed by layered silicate. The least reinforcing effect was obtained for the samples filled with boehmite nanoparticles. Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 103-108 DOI: http://dx.doi.org/10.3126/njst.v13i2.7721


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.


2018 ◽  
Vol 913 ◽  
pp. 522-528 ◽  
Author(s):  
Yong Wang ◽  
Kai Ming Cheng ◽  
Ji Xue Zhou ◽  
Wei Hong Li ◽  
Jin Huan Xia

In this paper, magnesium matrix composite with different AlN particles content were fabricated by powder metallurgy. The microstructure of composites was investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The mechanical properties of composites were measured by electronic universal testing machine. The results show that the best densification and the highest mechanical properties of composites reached when the addition of 6wt.% reinforcement at 620 °C for 1 hour. Additionally, the compressive strength and bending strength of composites were 217.06 MPa and 207.40 MPa respectively, increased by 79.2% and 91.12% compared with matrix alloy, and the reinforcement particles uniformly distributed in the matrix alloy. It may be concluded that the strengthening mechanism of composites is mainly attributed to grain refinement, load transfer, and dislocation strengthening.


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