EPDM/CIIR Blends: Compatibility, Morphology and Physical Properties

A detailed study of the blends of ethylene-propylene-diene rubber (EPDM) and chlorobutyl rubber (CIIR) is proposed in this study. These blends may find application in the manufacture of curing diaphragms/curing envelopes for tire curing applications. EPDM possesses better physical properties such as high heat resistance, ozone resistance, cold and moisture resistance, high resistance to permanent defonnation, very good resistance to flex cracking and impact. Because of the low gas and moisture penneability, good weathering resistance and high thermal stability of CIIR, blends of EPDM with CIlR may be attractive, if sufficient mechanical strength can be developed. Although a lot of work has been done on elastomer blends, studies on the blends of EPDM and CIIR rubbers are meagre. Hence in this investigation it is proposed to make a systematic study on the characteristics of EPDM and CIIR rubber blends.The mechanical and physical properties of an elastomer blend depend mainly on the blend compatibility. So in the first part of the study, it is proposed to develop compatible blends of EPDM with CIIR. Various commercial grades of ethylenepropylene- diene rubber are proposed to be blended with a specific grade of chlorobutyl rubber at varying proportions. The extent of compatibility in these blends is proposed to be evaluated based on their mechanical properties such as tensile strength, tear strength and ageing resistance. In addition to the physical property measurements, blend compatibility is also proposed to be studied based on the glass transition behavlour of the blends in relation to the Tg's of the individual components using Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The phase morphology of the blends is also proposed to be investigated by Scanning Electron Microscopy (SEM) studies of the tensile fracture surfaces. In the case of incompatible blends, the effect of addition of chlorosulfonated polyethylene as a compatibiliser is also proposed to be investigated.In the second part of the study, the effect of sulphur curing and resin curing on the curing behaviour and the vulcanizate properties of EPDM/CIIR blends are planned to be evaluated. Since the properties of rubber vulcanizates are determined by their network structures, it is proposed to determine the network structure of the vulcanizates by chemical probes so as to correlate it with the mechanical properties.In the third part of the work, the effect of partial precuring of one of the components prior to blending as a possible means of improving the properties of the blend is proposed to be investigated. This procedure may also help to bring down the viscosity mismatch between the constituent e1astomers and provide covulcanization of the blend.The rheological characteristics and processability of the blends are proposed to be investigated in the last part of the study. To explore their possible applications, the air permeability of the blend samples at varying temperatures is proposed to be measured. The thermal diffusivity behaviour of EPDM/CIlR blends is also proposed to be investigated using novel laser technique. The thermal diffusivity of the blends along with the thermal degradation resistance may help to determine whether the blends are suitable for high temperature applications such as in the manufacturing of curing envelope.

Prevalence and antimicrobial resistance of Salmonella enteritidis and other salmonellas in the eggs and egg-storing trays from retails markets of Coimbatore, South India

A study was conducted to determine the incidence of Salmonella enterica serovar Enteritidis and other Salmonella serovars on eggshell, egg contents and on egg-storing trays. A total of 492 eggs and 82 egg-storing trays were examined over a period of 1 year from different retail outlets of a residential area of Coimbatore city, South India. Salmonella contamination was recorded in 38 of 492 (7.7%) eggs out of which 29 was in eggshell (5.9%) and 9 in egg contents (1.8%). Around 7.5% of the egg-storing trays were also found to be contaminated with Salmonella. Serotyping of the Salmonella strains showed that 89.7% of the strains from eggshell, 100% of the strains from egg contents and 71.4% of the strains from egg-storing trays were Salmonella Enteritidis. Other serovarvars encountered were S. Cerro, S. Molade and S. Mbandaka from eggshell and S. Cerro from egg-storing trays. Seasonal variations in the prevalence pattern were identified with, a higher prevalence during monsoon months followed by post-monsoon and premonsoon. Further examination of the Salmonella strains was carried out by testing their antimicrobial sensitivity against 10 commonly used antimicrobials. Results revealed high prevalence of multiple antimicrobial resistance among these strains suggesting possible prior selection by use of antimicrobials in egg production

Prevalence and antimicrobial resistance of Salmonella enteritidis and other salmonellas in the eggs and egg-storing trays from retails markets of Coimbatore, South India

A study was conducted to determine the incidence of Salmonella enterica serovar Enteritidis and other Salmonella serovars on eggshell, egg contents and on egg-storing trays. A total of 492 eggs and 82 egg-storing trays were examined over a period of 1 year from different retail outlets of a residential area of Coimbatore city, South India. Salmonella contamination was recorded in 38 of 492 (7.7%) eggs out of which 29 was in eggshell (5.9%) and 9 in egg contents (1.8%). Around 7.5% of the egg-storing trays were also found to be contaminated with Salmonella. Serotyping of the Salmonella strains showed that 89.7% of the strains from eggshell, 100% of the strains from egg contents and 71.4% of the strains from egg-storing trays were Salmonella Enteritidis. Other serovarvars encountered were S. Cerro, S. Molade and S. Mbandaka from eggshell and S. Cerro from egg-storing trays. Seasonal variations in the prevalence pattern were identified with, a higher prevalence during monsoon months followed by post-monsoon and premonsoon. Further examination of the Salmonella strains was carried out by testing their antimicrobial sensitivity against 10 commonly used antimicrobials. Results revealed high prevalence of multiple antimicrobial resistance among these strains suggesting possible prior selection by use of antimicrobials in egg production

Mathematical Morphology on Hypergraphs Using Vertex-Hyperedge Correspondence

The focus of this paper is to develop computationally efficient mathematical morphology operators on hypergraphs. To this aim we consider lattice structures on hypergraphs on which we build morphological operators. We develop a pair of dual adjunctions between the vertex set and the hyperedge set of a hypergraph , by defining a vertex-hyperedge correspondence. This allows us to recover the classical notion of a dilation/erosion of a subset of vertices and to extend it to subhypergraphs of . This paper also studies the concept of morphological adjunction on hypergraphs for which both the input and the output are hypergraphs