Effect of Blowing Agent and Polyethylene Glycol on Cellular Structure and Mechanical Properties of Chloroprene Rubber

2012 ◽  
Vol 217-219 ◽  
pp. 517-521 ◽  
Author(s):  
Hong Ling Yi ◽  
Ting Wei ◽  
Lin Heng ◽  
Bai Cun Zheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Polyethylene Glycol ◽  
Cellular Structure ◽  
Foaming Agent ◽  
Blowing Agent ◽  
Swell Ratio ◽  
Closed Cell ◽  
Chloroprene Rubber

In this paper the closed-cell sponge of chloroprene rubber(CR) were produced by foaming agent Azodicarbonamide (AC) and Oxybis (benzene sulfonyl) hydrazide (OBSH). The blend blowing agent AC/OBSH was more effective than the pure AC as it could produce chloroprene foam with greater cell porosity, more uniform and better cell distributions. The CR foam prepared with AC/OBSH had better tensile strength and tear strength than pure AC, but higher Shore C hardness. The Polyethyene glycol (PEG) modified Zinc Oxide (ZnO) could accelerate curing and foam process simultaneously. Increase the content of PEG, CR foam has bigger swell ratio, smaller cell size, and better softness.

Phenolic Foam from Liquefied Products of Walnut Shell in Phenol

2011 ◽  
Vol 236-238 ◽  
pp. 241-246 ◽  
Author(s):  
Yuan Bo Huang ◽  
Zhi Feng Zheng ◽  
Hao Feng ◽  
Hui Pan
Keyword(s):  
Mechanical Properties ◽  
Reaction Temperature ◽  
Cellular Structure ◽  
Tween 80 ◽  
High Yield ◽  
Walnut Shell ◽  
Blowing Agent ◽  
Phenolic Foam ◽  
Resol Resin ◽  
Alkaline Conditions

The resol-type resin was prepared with a high yield from the liquefied products of walnut shell in phenol, which was reacted with formaldehyde under low alkaline conditions. The effects of reaction temperature and time on the yield and viscosity of the resol resin were investigated. Results showed that the optimum resol resinification conditions were a reaction temperature of 80°C and a reaction time of 2 h. The biomass-based resol resin from liquefied products of walnut shell was successfully applied to produce phenolic foam with diisopropyl ether as the blowing agent, Tween 80 as the surfactant and hydrochloric acid as the catalyst, respectively. The obtained foams showed satisfactory mechanical properties and a uniform fine cellular structure.

scholarly journals Preparation and properties of silicone rubber materials with foam/solid alternating multilayered structures

2021 ◽  
Author(s):  
Wenhuan Zhang ◽  
Zhaoping Deng ◽  
Hongwei Yuan ◽  
Shikai Luo ◽  
Huayin Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silicone Rubber ◽  
Cellular Structure ◽  
Cellular Structures ◽  
Compressive Property ◽  
Solid Layer ◽  
Multilayered Structures ◽  
Element Analysis ◽  
Morphology And Mechanical Properties

AbstractIn this paper, silicone rubber materials with foam/solid alternating multilayered structures were successfully constructed by combining the two methods of multilayered hot-pressing and supercritical carbon dioxide (SCCO2) foaming. The cellular morphology and mechanical properties of the foam/solid alternating multilayered silicone rubber materials were systematically studied. The results show that the growth of the cell was restrained by the solid layer, resulting in a decrease in the cell size. In addition, the introduction of the solid layer effectively improved the mechanical properties of the microcellular silicone rubber foam. The tensile strength and compressive strength of the foam/solid alternating multilayered silicone rubber materials reached 5.39 and 1.08 MPa, which are 46.1% and 237.5% of the pure silicone rubber foam, respectively. Finite element analysis (FEA) was applied and the results indicate that the strength and proportion of the solid layer played important roles in the tensile strength of the foam/solid alternating multilayered silicone rubber materials. Moreover, the small cellular structures in silicone rubber foam can provided a high supporting counterforce during compression, meaning that the microcellular structure of silicone rubber foam improved the compressive property compared to that for the large cellular structure of silicone rubber foam.

Temperature dependency of the long-term thermal conductivity of spray polyurethane foam

2021 ◽  
pp. 174425912110454
Author(s):  
Neal Holcroft
Keyword(s):  
Thermal Conductivity ◽  
Polyurethane Foam ◽  
Cellular Structure ◽  
Gas Diffusion ◽  
Temperature Dependent ◽  
Blowing Agent ◽  
Closed Cell ◽  
Wall Assembly ◽  
Cell Foam

The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.

scholarly journals A Robust, Tough and Multifunctional Polyurethane/Tannic Acid Hydrogel Fabricated by Physical-Chemical Dual Crosslinking

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 239 ◽  
Author(s):  
Jie Wen ◽  
Xiaopeng Zhang ◽  
Mingwang Pan ◽  
Jinfeng Yuan ◽  
Zhanyu Jia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polyethylene Glycol ◽  
Hydrogen Bonds ◽  
Tannic Acid ◽  
Hydroxyl Groups ◽  
Self Healing ◽  
Physical Chemical ◽  
Biomedical Field ◽  
Physical Crosslinking

Commonly synthetic polyethylene glycol polyurethane (PEG–PU) hydrogels possess poor mechanical properties, such as robustness and toughness, which limits their load-bearing application. Hence, it remains a challenge to prepare PEG–PU hydrogels with excellent mechanical properties. Herein, a novel double-crosslinked (DC) PEG–PU hydrogel was fabricated by combining chemical with physical crosslinking, where trimethylolpropane (TMP) was used as the first chemical crosslinker and polyphenol compound tannic acid (TA) was introduced into the single crosslinked PU network by simple immersion process. The second physical crosslinking was formed by numerous hydrogen bonds between urethane groups of PU and phenol hydroxyl groups in TA, which can endow PEG–PU hydrogel with good mechanical properties, self-recovery and a self-healing capability. The research results indicated that as little as a 30 mg·mL−1 TA solution enhanced the tensile strength and fracture energy of PEG–PU hydrogel from 0.27 to 2.2 MPa, 2.0 to 9.6 KJ·m−2, respectively. Moreover, the DC PEG–PU hydrogel possessed good adhesiveness to diverse substrates because of TA abundant catechol groups. This work shows a simple and versatile method to prepare a multifunctional DC single network PEG–PU hydrogel with excellent mechanical properties, and is expected to facilitate developments in the biomedical field.

Effect of reactive and non-reactive diluents on thermal and mechanical properties of epoxy resin

2017 ◽  
Vol 30 (10) ◽  
pp. 1159-1168 ◽  
Author(s):  
Animesh Sinha ◽  
Nazrul Islam Khan ◽  
Subhankar Das ◽  
Jiawei Zhang ◽  
Sudipta Halder
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Polyethylene Glycol ◽  
Epoxy Resin ◽  
Mechanical Performance ◽  
Thermal And Mechanical Properties ◽  
Minor Variation ◽  
Reactive Diluents

The effect of reactive (polyethylene glycol) and non-reactive (toluene) diluents on thermal and mechanical properties (tensile strength, hardness and fracture toughness) of diglycidyl ether of bisphenol A epoxy resin (cured by triethylenetetramine) was investigated. The thermal stability and mechanical properties of the epoxy resin modified with reactive and non-reactive diluents at different wt% were investigated using thermo-gravimetric analyser, tensile test, hardness test and single-edge-notched bend test. A minor variation in thermal stability was observed for epoxy resin after addition of polyethylene glycol and toluene at 0.5 wt%; however, further addition of reactive and non-reactive diluents diminished the thermal stability. The addition of 10 wt% of polyethylene glycol in epoxy resin significantly enhances the tensile strength (∼12%), hardness (∼14%) and fracture toughness (∼24%) when compared to that of neat epoxy resin. In contrast, major drop in mechanical performance was observed after addition of toluene in epoxy. Furthermore, fracture surfaces were investigated under field emission scanning electron microscope to elucidate the failure mechanism.

scholarly journals Effect of Chemical Blowing Agent on the PVC Cellular Coating Extrusion

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5752
Author(s):  
Tomasz Garbacz ◽  
Aneta Tor-Świątek ◽  
Tomasz Jachowicz
Keyword(s):  
Mechanical Properties ◽  
Outer Surface ◽  
Cellular Structure ◽  
Steel Wire ◽  
Direct Impact ◽  
Blowing Agent ◽  
Process Characteristics ◽  
Modified Polymers ◽  
Thin Walled ◽  
Extrusion Product

Depending on the type and application, the coatings of power, electric, telecommunication cables as well as other types of conduits are made of various kinds of polymer plastics. However, most often, because of good mechanical properties and many other advantages, they are first of all made from polyvinyl chlorine (PVC). This paper contains characteristics of the developed cellular extrusion of cable coatings, as well as specification of the blowing agent (BA) used and selected research results of the obtained cellular extrusion product. In technological tests the coating extrusion technological line was used. The material was modified with a new blowing agent of exothermic distribution of process characteristics, which was introduced into the material in quantities from 0.2 to 0.6% wt. The amount of blowing agent used has a direct impact on the density and structure of the received result for the extrusion of modified polymers. The cellular structure of the cellular coatings was presented. The results of the study are thin-walled properties of single- and double-layer cellular outer coatings, forming an outer surface on a steel wire. The research on the structure of manufactured materials, density and the degree of porosity, water and oil absorptivity, mechanical strength is presented.

Reinforcement of Natural Rubber with Silanized Precipitated Silica Nanofiller

2005 ◽  
Vol 78 (5) ◽  
pp. 793-805 ◽  
Author(s):  
A. Ansarifar ◽  
N. Ibrahim ◽  
M. Bennett
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Reaction Mechanism ◽  
Energy Density ◽  
Natural Rubber ◽  
Elemental Sulfur ◽  
Stored Energy ◽  
Tear Strength ◽  
Precipitated Silica

Abstract The effect of a large amount of precipitated amorphous white silica nanofiller, pre-treated with bis[3-triethoxysilylpropyl-)tetrasulfide (TESPT), on the mechanical properties of a sulfur-cured natural rubber (NR) was studied. TESPT chemically adheres silica to rubber and also prevents silica from interfering with the reaction mechanism of sulfur-cure. The silica particles were fully dispersed in the rubber, which was cured primarily by using sulfur in TESPT, or, by adding a small amount of elemental sulfur to the cure system. The cure was also optimized by incorporating sulphenamide accelerator and zinc oxide into the rubber. The hardness, tear strength, tensile strength, and stored energy density at break of the vulcanizate were substantially improved when the filler was added. Interestingly, these properties were also enhanced when the rubber was cured primarily by using sulfur in TESPT.

Effects of dynamic mold temperature control on melt pressure, cellular structure, and mechanical properties of microcellular injection-molded parts: An experimental study

2019 ◽  
Vol 38 (5-6) ◽  
pp. 111-130
Author(s):  
Guiwei Dong ◽  
Guoqun Zhao ◽  
Junji Hou ◽  
Guilong Wang ◽  
Yue Mu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Temperature Control ◽  
Cellular Structure ◽  
Weld Line ◽  
Mold Temperature ◽  
Cell Diameter ◽  
Cooling Stage ◽  
Molded Parts

In this work, the effects of dynamic mold temperature control (DMTC) on melt pressure, cellular structure, and mechanical properties of microcellular injection molding (MIM)-molded parts are investigated experimentally. It is found that with the increase of the mold temperature, the duration of foaming pressure in the cooling stage increases. Meanwhile, the average cell diameter and cell diameter dispersion increases as well as the cell density decreases in MIM molded parts. The turning point of mold temperature after which the foaming pressure in the cooling stage and the cellular structure in MIM molded parts generate a significant change is around the glass transition temperature of the used plastic material. Under DMTC conditions, with the increase of mold temperature, the tensile strength, flexural strength, and impact strength of MIM molded specimens of single gate without weld line change a little, while the tensile strength, flexural strength of MIM molded specimens of double gates with weld line increase obviously. When the mold temperature increases to 120°C and over, the tensile strength, flexural strength of MIM molded specimens of double gates with weld line reach an equivalent level of specimens of single gate without weld line.

Effect of Polyethylene Glycol (PEG) on Molten Plasticized Cellulose Acetate (CA)

2013 ◽  
Vol 830 ◽  
pp. 172-175
Author(s):  
Cheng Zhi Chuai ◽  
Zhi Zhang
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Polyethylene Glycol ◽  
Flexural Strength ◽  
Cellulose Acetate ◽  
Flexural Modulus ◽  
Degree Of Polymerization ◽  
Maximum Elongation ◽  
Elongation At Break

Ethylene glycol (EG) and polyethylene glycol (PEG) were added as plasticizers to improve the processing performance of cellulose acetate (CA). The CA with 30% plasticizers were melted by HAAKE at 200 °C. The effects of EG and PEG (degree of polymerization in 200-800) on rheological properties and mechanical properties of CA were investigated. The results show that the plasticizing time, equilibrium torque and melt viscosity of the plasticizing system increase with the increase of PEG molecular weight, while the processing performance decreased. The tensile strength of the system decrease as the PEG molecular weight increased. The plasticizing system which contents 30% PEG-200(degree of polymerization is 200) shows the maximum elongation at break. The minimum values appeared in both flexural strength and flexural modulus in the CA/PEG-200 system.

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