Preparation and characterization of incompletely condensed POSS and its application in RTV composites

2016 ◽  
Vol 49 (2) ◽  
pp. 157-172 ◽  
Author(s):  
Zhanglin Yuan ◽  
Jincheng Wang
Keyword(s):  
Tensile Strength ◽  
Mass Loss ◽  
Mass Loss Rate ◽  
Three Dimensional ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Amorphous Structure ◽  
Proton Nuclear Magnetic Resonance ◽  
Elongation At Break ◽  
H Nmr

Research on the structure and properties of room-temperature vulcanizated silicone rubber (RTV) composites with a type of incompletely condensed polyhedral oligomeric silsesquioxane (POSS) was conducted. Trisilanolphenyl POSS (TPOSS) was synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), proton nuclear magnetic resonance (1H NMR), and scanning electron microscopy (SEM). FTIR spectra suggested successful bonding of TPOSS. XRD analysis illustrated that POSS exhibited a crystal behavior while TPOSS had an amorphous structure. The chemical shift of 1H NMR at 7.1–7.8 ppm and 3.71–3.73 ppm further confirmed the structure of TPOSS. TPOSS particle was aggregated with large size observed from SEM Then, TPOSS was applied in RTV composites. Properties of RTV/TPOSS composites such as swelling behavior, tensile strength, elongation at break, thermal stability, and flame retardance were researched and compared. Results showed that the TPOSS were beneficial for increasing the cross-linking points and forming the effective three-dimensional networks in RTV composites. Tensile tests revealed that the tensile strength of RTV/TPOSS-3 was 20% higher than that of pure RTV, and the elongation at break of RTV/TPOSS-1 also showed an improvement. Thermogravimetric analysis studies demonstrated that RTV/TPOSS-5 presented the highest values of temperature at 5% mass loss and temperature at maximum mass loss rate of 437.5°C and 573.7°C, respectively. In addition, the residue of RTV/TPOSS-9 increased to 61.0%. Horizontal burning test found that the burning rate with 9% content of TPOSS was strikingly decreased by 66.4% compared with pure RTV.

Mechanochemical Devulcanization of Vulcanized Gum Natural Rubber

2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Three Dimensional ◽  
Elongation At Break ◽  
Tear Strength ◽  
Vulcanized Rubber ◽  
Dimensional Network ◽  
Polymeric Chains ◽  
Cure Time

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.

scholarly journals New Materials for 3D-Printing Based on Polycaprolactone with Gum Rosin and Beeswax as Additives

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 334 ◽  
Author(s):  
Cristina Pavon ◽  
Miguel Aldas ◽  
Juan López-Martínez ◽  
Santiago Ferrándiz
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Mechanical Characterization ◽  
Three Dimensional ◽  
New Materials ◽  
Elongation At Break ◽  
Printing Process ◽  
Gum Rosin ◽  
The Matrix ◽  
Natural Additives

In this work, different materials for three-dimensional (3D)-printing were studied, which based on polycaprolactone with two natural additives, gum rosin, and beeswax. During the 3D-printing process, the bed and extrusion temperatures of each formulation were established. After, the obtained materials were characterized by mechanical, thermal, and structural properties. The results showed that the formulation with containing polycaprolactone with a mixture of gum rosin and beeswax as additive behaved better during the 3D-printing process. Moreover, the miscibility and compatibility between the additives and the matrix were concluded through the thermal assessment. The mechanical characterization established that the addition of the mixture of gum rosin and beeswax provides greater tensile strength than those additives separately, facilitating 3D-printing. In contrast, the addition of beeswax increased the ductility of the material, which makes the 3D-printing processing difficult. Despite the fact that both natural additives had a plasticizing effect, the formulations containing gum rosin showed greater elongation at break. Finally, Fourier-Transform Infrared Spectroscopy assessment deduced that polycaprolactone interacts with the functional groups of the additives.

scholarly journals Evaluation of the Performance Degradation of Hybrid Steel-Polypropylene Fiber Reinforced Concrete under Freezing-Thawing Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Daming Luo ◽  
Yan Wang ◽  
Ditao Niu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Mass Loss ◽  
Frost Resistance ◽  
Rough Set Theory ◽  
Mass Loss Rate ◽  
Splitting Tensile Strength ◽  
Fiber Reinforced Concrete ◽  
Hybrid Fibers ◽  
Flexural Toughness

The reasonable inclusion of hybrid fibers can leverage the advantages of each kind of fiber and enhance the frost resistance and flexural toughness of concrete. Previous studies on hybrid steel-polypropylene fiber reinforced concrete (HSPFRC) focused primarily on its mechanics instead of its frost resistance. In this work, the compressive strength, splitting tensile strength, mass loss rate, relative dynamic elastic modulus (RDEM), and flexural toughness of HSPFRC after freezing-thawing (F-T) are studied, and the relative importance of each factor affecting the frost resistance of HSPFRC is quantified by using fuzzy rough set theory. The results show that the inclusion of hybrid fibers has a noticeable effect on the frost resistance of HSPFRC after hundreds of F-T cycles and that the effect on the splitting tensile strength is greater than that on the compressive strength. After 500 F-T cycles, as the steel fiber (SF) content increases, the compressive strength and splitting tensile strength increase by factors of approximately 5 and 4, respectively, the flexural toughness is strengthened, and the mass loss rate is reduced by more than 90%. The addition of polypropylene fibers (PFs) has a relatively small effect on the strength of HSPFRC but reduces the mass loss of HSPFRC by almost 80%. However, the suitability of the RDEM for evaluating the frost resistance of HSPFRC remains uncertain. Quantified by fuzzy rough set theory, the weights of the factors affecting the frost resistance of HSPFRC are 0.50 (number of F-T cycles) > 0.35 (SF content) > 0.15 (PF content), verifying the experimental results.

scholarly journals The Study of Recycled Ethylene Propylene Diene Monomer (EPDM-r)/Polypropylene (PP) Polymeric Blends

2021 ◽  
Vol 2080 (1) ◽  
pp. 012012
Author(s):  
MH Zulkifli ◽  
MSM Rasidi ◽  
NAM Rahim ◽  
L Musa ◽  
Abdul Hakim Masa
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Young’S Modulus ◽  
Morphological Study ◽  
Young's Modulus ◽  
Tensile Tests ◽  
Ethylene Propylene Diene Monomer ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
Polymeric Blends

Abstract In this study, recycled ethylene propylene diene monomer (EPDM-r) were blended with polypropylene (PP) by compounding via heated two roll mills with the various ratio of EPDM-r. Certain blends were included with PP-g-MA as a compatibilizer. In tensile tests, the increasing of EPDM-r content in blends resulted in the reduction of tensile strength and Young’s Modulus but increased elongation at break. Furthermore, the presence of compatibilizer in blends enhanced the tensile properties. It was found all the samples with compatibilizer performs better results in tensile strength, Young’s Modulus, and elongation at break than samples without compatibilizer. On the other hand, the aging affected were studied on compatibilized and uncompatibilized blends. It was found that aging affects the samples by decreasing the tensile strength, Young’s Modulus, and elongation at break. The crosslink density had been found higher in the blends with high EPDM-r content as the EPDM-r had the ability to swell. The morphological study related to the structure with the tensile properties. It was confirmed that the presence of a compatibilizer increased the compatibility between EPDM-r and PP matrix.

scholarly journals Analysis of Some Mechanical Properties of Hybrid Matrix Composites Reinforced by Linen Fabric. Orthopaedic Applications

2021 ◽  
Vol 58 (3) ◽  
pp. 148-159
Author(s):  
Vlad Alexandru Georgeanu ◽  
Dumitru Bolcu ◽  
Marius Marinel Stanescu ◽  
Ion Ciuca ◽  
Victorita Stefanescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Materials ◽  
Tensile Tests ◽  
Matrix Composites ◽  
Characteristic Curves ◽  
Elongation At Break ◽  
Fabric Reinforcement ◽  
Hybrid Matrix ◽  
Linen Fabric

Great interest has been shown lately in bio-composite materials because they are inexpensive and sustainable. Composites with matrices and natural reinforcers have been little studied. Here, we study certain mechanical properties of composite materials with a Dammar-based matrix (also named hybrid matrix) and flax fabric reinforcement. To be precise, we examine three types of resins where Dammar is the major component, with a volume proportion of 55%, 65% and 75%. In this respect, we have made composite materials reinforced by two types of flax fabric and we have measured the characteristic curves and some mechanical properties, such as the Young�s modulus, tensile strength and elongation at break using tensile tests. Based on the obtained properties, it is proposed or possible to use these materials in orthopedics.

Research on Mechanical Properties and Wear Behavior at Extremely Low Temperature of a 16Cr-6Ni Austenitic Steel

2017 ◽  
Vol 898 ◽  
pp. 791-796
Author(s):  
Wei Gang Zhao ◽  
Guo Liang Xie ◽  
Qiang Song Wang ◽  
Dong Mei Liu
Keyword(s):  
Tensile Strength ◽  
Wear Behavior ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Impact Behavior ◽  
Dislocation Network ◽  
Plastic Behavior ◽  
Face Centered Cubic ◽  
The Matrix

The tensile strength and plastic behavior of the Cr16Ni6 steel were investigated at 298K (298K) and 76K. The yield strength and tensile strength of the alloy increased significantly with lower temperatures, from 990 MPa to 1350 MPa and from 1313 MPa to over 1800 MPa, respectively. Young’s modulus and impact behavior were found when testing temperature decreased. It was revealed from the microstructure observation conducted by scanning electron microscopy (SEM) and x-ray diffraction technique (XRD) analysis that the face-centered-cubic (FCC) structure of the matrix remained stable with a very small amount of tangent phase transformation to martensitie during the tensile tests at 76 K. The matrix grains deformed at 298K were cut apart into many small sub-grains with similar crystallographic orientation in the size of only 60-200 nm wide. Very small amount of dislocation cells or bands observed in the specimens deformed at 76 K, although many sub-grains and areas containing dislocation network were found. The formation of twin-structures along the 1/3(420) planes was found in the deformation areas at 76 K. The improvement of strength was mainly attributed to the fact that it was more difficult for the dislocation slipping along lattice planes at 76 K than at 298K, due to the reduction of the movement and diffusion abilities of atoms. The friction coefficient was found to be a little higher at 93 K than at 298 K due to the bad lubricity of the graphite material at cryogenic temperature.

Preparation and Mechanical Properties Study of Blown Film from Star Copolymer of Poly(Epsilon-Caprolactone-co-L-Lactide)

2013 ◽  
Vol 750-752 ◽  
pp. 1934-1937
Author(s):  
Shi Qi Liu ◽  
Lin Jiang ◽  
Ying Jie Zhang ◽  
Ming Long Yuan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Screw Extruder ◽  
Spectra Analysis ◽  
Elongation At Break ◽  
H Nmr ◽  
Single Screw Extruder ◽  
Star Copolymers ◽  
Blown Film ◽  
Star Copolymer

Star copolymers of ε-caprolactone and L-lactide (ε-CL/L-LA) were synthesized with different compositions in the presence of pentaerythritol and using stannous octoate as catalyst. The copolymers were characterized by1H NMR spectra analysis and then blown into films in a single-screw extruder. The mechanical properties study show that the copolymers differed widely in their elongation at break and tensile strength according to the ratio of monomers and pentaerythritol in the copolymerization. The tensile strength of the films deriving from extrusion is much higher than that obtained through solvent volatilization.

scholarly journals Preparation of Cassava Bagasse Starch-Based Biodegradable Film Reinforced with Chicken Feet Gelatin, Citric Acid as Crosslinker, and Glycerol as Plasticizer

2018 ◽  
Vol 18 (4) ◽  
pp. 688 ◽  
Author(s):  
Silviana Silviana ◽  
Piontek Benedictus Brandon ◽  
Bella Ayu Silawanda
Keyword(s):  
Tensile Strength ◽  
Citric Acid ◽  
Mass Loss ◽  
Gravimetric Analysis ◽  
Biodegradable Films ◽  
Citric Acid Concentration ◽  
Elongation At Break ◽  
Good Thermal Stability ◽  
Cassava Bagasse ◽  
Higher Temperature

Chicken feet is one of sources used to produce biodegradable films due to inexpensive and abundant source. Chicken feet contains extracted gelatin amount of 27.61 to 33%. This biofilm was prepared from cassava bagasse starch with citric acid as cross-linker and glycerol as plasticizer. Cassava bagasse contains about 40–64% of starch. This paper observes the optimum composition of cassava bagasse starch-based biofilm preparation upon Central Composite Design with variables of gelatin, glycerol, and citric acid concentration with response of tensile strength and elongation at break. This research was executed in several steps, i.e. extraction of gelatin, extraction of cassava bagasse starch, and casting. Optimum condition of this biofilm preparation can be obtained at 12.98% w of gelatin content, 0.22% w of glycerol and 0.27% w of citric acid by releasing 21.73 MPa of tensile strength and 19.73% of elongation at break. Mass loss of biofilm with lower gelatin content gave almost the same mass loss for blank biofilm (cassava bagasse starch-based without gelatin content). Increasing of gelatin content in the biofilm, increasing of the biofilm mass loss. However, the biofilm had good thermal stability by thermal gravimetric analysis with higher temperature to obtain inorganic residue than that of blank biofilm.

scholarly journals Corrosion Performance of Nano-TiO2-Modified Concrete under a Dry–Wet Sulfate Environment

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5900
Author(s):  
Chao Xu ◽  
Hao-Hao Liao ◽  
You-Liang Chen ◽  
Xi Du ◽  
Bin Peng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Peak Stress ◽  
Xrd Analysis ◽  
Concrete Surface ◽  
Test Results ◽  
Nano Tio2 ◽  
Ordinary Concrete

This study compared the effects of the sulfate dry–wet cycle on the properties of ordinary concrete and nano-TiO2-modified concrete, including the mass loss rate, ultrasonic wave velocity, compressive strength, and XRD characteristics. In addition, a series of compression simulations carried out using the PFC2D software are also presented for comparison. The results show the following: (1) with an increase in dry–wet cycles, the damage to the concrete gradually increased, and adding nano-TiO2 into ordinary concrete can improve the material’s sulfate resistance; (2) after 50 sulfate dry–wet cycles, the mass loss rate of ordinary concrete was –3.744%, while that of nano-TiO2-modified concrete was −1.363%; (3) the compressive strength of ordinary concrete was reduced from 41.53 to 25.12 MPa (a reduction of 39.51%), but the compressive strength of nano-TiO2-modified concrete was reduced from 49.91 to 32.12 MPa (a reduction of 35.64%); (4) after a sulfate dry–wet cycle, the nano-TiO2-modified concrete surface produced white crystalline products, considered to be ettringite based on the XRD analysis; (5) when considering the peak stress and strain of the concrete samples, the numerical results agreed well with the test results, indicating the reliability of the method.

Temporary-Creep and Post-Creep Properties of Aquaculture Netting Materials With UHMWPE Fibres

2013 ◽  
Author(s):  
Heidi Moe Føre ◽  
Per Christian Endresen ◽  
Østen Jensen
Keyword(s):  
Tensile Strength ◽  
Room Temperature ◽  
Breaking Strength ◽  
Tensile Tests ◽  
Test Results ◽  
Load History ◽  
Elongation At Break ◽  
Creep Properties ◽  
Mean Values ◽  
Creep Strains

This paper presents test results on temporary-creep properties, recovery of strain post creep and post-creep tensile properties of a Raschel knitted netting material with a combination of UHMWPE and Polyester fibres. Specimens of the material were subjected to uniaxial loading over a period of 30 minutes, at a constant creep target load of 10–90 % of average tensile strength. The specimens were wet and tested in room temperature. The netting structure experienced significant creep strain, with mean values in the range of 1.3–4.5 %, increasing with increased creep target load. Large proportions of the elongation accumulated during on-loading and creep were long lasting and possibly permanent. Tensile tests showed that for the highest creep target load, strength and elongation at break increased by 17 %. The UHMWPE-netting experienced larger creep strains than PA6-netting for relatively large creep target loads (60–90 % of the average breaking strength), while creep strains were smaller for low loads. PA6-netting had a larger and faster recovery of strain post creep than the UHMWPE-netting, and the length and force at break were not significantly affected by the creep load history.

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