in many processes polymeric foams can be produced by using chemical or physical blowing agents. in this work for polyethylene foam production, the chemical blowing agents and compression moulding process were employed. at first, by using dsc diagram of two polyethylene grades, a suitable polyethylene grade was selected for foam production and then we discuss about blowing agent critical percent...

the effect of shear rate on dissolution of carbon dioxide in viscoelastic wheat flour matrix and cell density in a glass barrel twin screw extruder is investigated. it is found that by increasing the shear rate there will be a decrease in the required thermodynamic conditions and hence, it improves blowing agent dissolution and increases the cell density. shear rate breaks up big bubbles and he...

The solubility of HFC 134a and HFC 152a in polystyrene melt was measured up to 800 psi at 150 C and 190 C. A magnetic suspension balance was used to experimentally measure the apparent solubility. The Simha-Somcynsky (SS) equation of state (EOS) was applied in the multi-components system to estimate the swollen volume. Consequently, the buoyancy compensation can be obtained to determine the sol...

Metal porous foams have been eliciting much interest in recent years due to their high capacity of energy absorption. The characteristics of the pores in these materials play an important role on their energy absorption capability and other properties. This study reports the fabrication of aluminum closed-cell foams by accumulative roll-bonding (ARB) technique using calcium carbonate (CaCO3) as...

Methylene chloride and CFCs are used as auxiliary blowing agents in the manufacture of flexible polyurethanefoams and are promptly emitted during the manufacturing processes.The concentrationof the auxiliary blowing agent are quite low due to the accepted practice of using large volumes of air to lower the ambient concentration of toxic isocyanates (a key chemical in the urethane reaction seque...

This study evaluated the effect of air-blowing variables on the microtensile bond strength (microTBS) of two all-in-one adhesives. A bonding agent was applied to the flat dentin surface of extracted bovine teeth, and the surface left undisturbed for 20 seconds. Gentle or intensive air-blowing was applied for five seconds, and the adhesive photopolymerized for 10 seconds. Resin composite paste w...

Clostridium tyrobutyricum is considered the main agent of late-blowing defect in the production of hard cheese. Here, we described the draft genome sequences and annotation of C. tyrobutyricum strain UC7086, which was isolated from Grana Padano cheese with blowing defect, and C. tyrobutyricum DSM 2637 type strain in a comparative study.

Refrigerators are the most energy demanding household devices since they working 7/24. Improving insulation material is crucial for reducing this demand. One of promising ways to improve materials develop better-blowing agents. In study, effects Liquid Blowing Agent (LBA) and Pentane (PBA) on whole refrigerator were investigated by experimental numerical methods. The thermal conductivities meas...