Effect of Compound Formulation and Processing Conditions on Properties of Extruded EPDM and NR/EPDM Foams

2003 ◽  
Vol 22 (1) ◽  
pp. 43-56 ◽  
Author(s):  
C. Lewis ◽  
Y. Rodlum ◽  
B. Misaen ◽  
S. Changchum ◽  
G.L.A. Sims
Keyword(s):  
Cell Structure ◽  
Decomposition Temperature ◽  
Processing Conditions ◽  
Structure And Properties ◽  
Foam Structure ◽  
Blowing Agent ◽  
Hot Air ◽  
Roll Mill ◽  
Type Composition ◽  
Extended Work

The effects of compound formulations and processing conditions on the structure and properties of extruded EPDM and EPDM/NR blends of tube foams were investigated. The foam tubes were prepared by mixing a compound in a two roll mill, extruding the compound through a cold feed extruder and finally vulcanizing the extrudate in a circulating hot air oven. In previous results, the EPDM grade, blowing agent type, composition of EPDM blend and processing conditions were found to affect the cell structure and the physical properties of the resultant EPDM foams. An extended work was carried out using blowing agent blends and NR blending with EPDM as a based rubber. The characteristics of blowing agent blends (ADC/DNPT) were studied using a gas evolution apparatus. Decomposition temperature of ADC decreased with both DNPT and OBSH blending which affected the resultant EPDM foams structure and properties. To promote the use of natural rubber, its various compositions were blended with EPDM to produce the foam tubes. Modified formulations were needed to ease the difficulty of mixing and stabilising the resultant foams. Using a tube mold for an extrudate as an alternative technique to vulcanize the NR/EPDM extrudate in the hot air oven was successfully found to control the expansion and foam dimensions. The NR compositions were also found to affect the foam structure and properties.

scholarly journals Processing of (Co)Poly(2-oxazoline)s by Electrospinning and Extrusion from Melt and the Postprocessing Properties of the (Co)Polymers

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 295 ◽  
Author(s):  
Wojciech Wałach ◽  
Natalia Oleszko-Torbus ◽  
Alicja Utrata-Wesołek ◽  
Marcelina Bochenek ◽  
Ewa Kijeńska-Gawrońska ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Molar Mass ◽  
Three Dimensional ◽  
Fused Deposition Modelling ◽  
Processing Conditions ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Gradient Copolymers ◽  
Fused Deposition

Poly(2-oxazoline) (POx) matrices in the form of non-woven fibrous mats and three-dimensional moulds were obtained by electrospinning and fused deposition modelling (FDM), respectively. To obtain these materials, poly(2-isopropyl-2-oxazoline) (PiPrOx) and gradient copolymers of 2-isopropyl- with 2-n-propyl-2-oxazoline (P(iPrOx-nPrOx)), with relatively low molar masses and low dispersity values, were processed. The conditions for the electrospinning of POx were optimised for both water and the organic solvent. Also, the FDM conditions for the fabrication of POx multi-layer moulds of cylindrical or cubical shape were optimised. The properties of the POx after electrospinning and extrusion from melt were determined. The molar mass of all (co)poly(2-oxazoline)s did not change after electrospinning. Also, FDM did not influence the molar masses of the (co)polymers; however, the long processing of the material caused degradation and an increase in molar mass dispersity. The thermal properties changed significantly after processing of POx what was monitored by increase in enthalpy of exo- and endothermic peaks in differential scanning calorimetry (DSC) curve. The influence of the processing conditions on the structure and properties of the final material were evaluated having in a mind their potential application as scaffolds.

scholarly journals Microstructural and Chemical Analysis of Polyurethane and Polyisocyanurate Foam Insulations

2021 ◽  
Author(s):  
Umberto Berardi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Cell Structure ◽  
Polymer Degradation ◽  
Chemical Characterization ◽  
Aging Behavior ◽  
Blowing Agent ◽  
Closed Cell ◽  
Physical Attributes ◽  
Cell Foam

For some closed cell foam insulation products, the thermal conductivity increases at low temperatures, contrary to single thermal resistance values provided by manufacturers. This phenomenon has been demonstrated in various polyurethane and polyisocyanurate insulations. The reduction in thermal performance has been attributed to the diffusion of air and blowing agent through the foam and to the condensation of blowing agent. Aging processes such as freeze-thaw cycling, moisture accumulation, and polymer degradation further increase thermal conductivity. The initial cell structure plays a role in dictating the thermal performance. To further understand the loss of thermal performance in closed cell foams, microstructure and chemical characterization was performed in this study. The aging behavior of foam insulations was analyzed by imaging foams with SEM and by measuring foam. Changes in the polymer physical attributes were identified and compared to increases in thermal conductivity. This project also used gas chromatography and quantified changes in pentane concentration in polyisocyanurate foams that have undergone aging

Structure and Properties of Modifier for Heat Transfer Printing on Cotton Fabric

2011 ◽  
Vol 331 ◽  
pp. 426-429
Author(s):  
Yi Mu ◽  
Lan Wang ◽  
Ming Hua Wu ◽  
Jun Xiong Lin
Keyword(s):  
Heat Transfer ◽  
Spherical Shape ◽  
Decomposition Temperature ◽  
Polymerization Process ◽  
Structure And Properties ◽  
Transfer Printing ◽  
Transmission Electron ◽  
Ft Ir ◽  
Regular Spherical Shape

Modifier for heat transfer printing on cotton fabrics was prepared by semi-continuous emulsion polymerization process with butyl acrylate (BA), styrene (St), acrylonitrile (AN) and cross-linking monomer. FT-IR characterization of modifier groups showed that individual monomer well carried out polymerization. Transmission electron microscopy (TEM) photos demonstrated that latex particles had regular spherical shape and uniform distribution. TGA curves indicated that thermal decomposition temperature of modifier was 439 oC. As for the transfer printing products had good colour fastness, high transfer rate and no formaldehyde.

Comparative Study on TiH2 and CaCO3 for Fabrication of Mg Alloy Foams

2008 ◽  
Vol 569 ◽  
pp. 273-276 ◽  
Author(s):  
Chang Hwan Seo ◽  
M. J. Jeong ◽  
In Young Jung ◽  
Bo Young Hur
Keyword(s):  
Metal Foam ◽  
High Strength ◽  
Cost Effective ◽  
Decomposition Temperature ◽  
Mg Alloy ◽  
New Materials ◽  
Alloying Element ◽  
Blowing Agent ◽  
Economic View ◽  
Cost Effective Method

Aluminum alloy foams, new materials belonging to a special class of porous materials, have been prepared using melt foaming method. Silicon was chosen alloying element due to its low density, high strength, effective casting and reduced shrinkage. Melt foaming method is cost-effective method to fabricate metal foam. Usually, TiH2 is applied to blowing agent, but its cost is high. CaCO3 is one of candidates to substitute TiH2 in the economic view-point. For the comparison of formability, Mg alloy foams were prepared by TiH2 and CaCO3. However, the decomposition temperature of CaCO3 is higher than that of TiH2. This paper will be discussed on the possible usage of CaCO3 in the Al melt.

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