Reactive Extrusion of Dynamic Elastoplastics on the Basis of Thermoplastic Polyolefins and Butyl Rubber

Abstract

The article deals with the influence of the concentration of butyl rubber and vulcanizing agents on the process of reactive extrusion of elastoplastics based on a mixture of thermoplastic polyolefins. The mechanic-chemical synthesis of dynamically vulcanized elastoplastics was carried out in the process of reactive extrusions. Single screw extruder with ratio L / D = 24 consists of 4 zones: loading zone, compression zone, dosing zone, extruder head. The number of turnovers of the screw was regulated using an asynchronous engine. The head is equipped with a slotted console enabling to obtain continuous sheets 2 mm thick and 100 mm wide. As thermoplastic polyolefins there was used the polyethylene of low density, polypropylene. Vulcanization of polymer mixtures was carried out using the dicumyl peroxide and sulfur. The mechanochemical synthesis of elastoplastics was carried out at different temperatures of the zones of material cylinder and extrusion pressure. The results of the study of the influence of extrusion process parameters on the melt flow rate of elastoplastics were presented. For a mixture of polyethylene and butyl rubber of low density the optimum temperature for zones of the material cylinder varied within 100 150 ° C, and the extrusion pressure was 5.2  7.0 MPa. For a mixture of polypropylene and butyl rubber the temperature regime varied within 140-210С and pressure of extrusion-7.2-9.4 МPа. To add elastoplastic properties to the polymer mixtures, vulcanizing agents such as dicumyl peroxide and sulfur were introduced into their composition. Selective influence of vulcanizing agents on the nature of changes of technological parameters of reactive extrusion and melt flow index was investigated. It found that dynamic vulcanic elastoplastics with unique compatibility of structures and properties can be obtained in at concentrations of dicumyl peroxide  0.5 wt.% or sulfur5.0wt.%. It revealed that dynamic vulcanic elastoplastics with unique compatibility of structures and properties can be obtained in the concentration of dicumyl peroxide 0.5 wt.% or sulfur 5.0wt.%. It established that the concentration of butyl rubber in

Molecular evolution during dynamic vulcanization of polyolefin mixtures for lead‐free thermoplastic vulcanized

“…Vulcanization of polyolefins is a well-known process and is widely used for producing rubber materials. 1,2 A similar process was used to produce thermoplastic vulcanisates (TPV) from mixtures of polyolefin elastomers and thermoplastics polymers 3 Since 1996, Mixer Spa has produced medium voltage (MV) insulation compounds based on EPDM and EPDM/LDPE blends which are now commercially available. 4,5 The complex materials with optimized thermoplastic elastomeric response were producer by MIXER in its laboratory by a structural design of composition followed by dynamic crosslinking.…”

“…Vulcanization of polyolefins is a well‐known process and is widely used for producing rubber materials . A similar process was used to produce thermoplastic vulcanisates (TPV) from mixtures of polyolefin elastomers and thermoplastics polymers Since 1996, Mixer Spa has produced medium voltage (MV) insulation compounds based on EPDM and EPDM/LDPE blends which are now commercially available .…”