Effect of Tensile Rate and Carbon Black on the Fracture of Natural Rubber and Styrene-Butadiene Rubber

Tensile strengths and ultimate elongations of both crystallizing NR and amorphous SBR increase with increasing tensile rate and increasing carbon black N115 loading, although the dependence of N115 loading is at least ten-fold stronger.Previous research has shown that edge-cut specimens of gum NR show an abrupt drop in tensile strength, when tested at 50 mm/min at a critical cut size, because of lack of time to crystallize in bulk. In this thesis, the behavior of critical cut size with respect to tensile rate is completed. Critical cut size increases monotonously, but not linearly, with increasing tensile rate. Changes in precut tensile strength of NR at various tensile rates are measured and compared with those of SBR. Previous research has shown a critical loading of N115 black tested at 50 mm/min, before which precut NR will only be weakened. In this thesis, precut tensile results of NR with various N115 black contents were measured and compared to those of SBR. Only NR shows an critical black loading to reinforce precut specimens and this concentration doesn’t change with tensile rate. Reinforcement of precut NR is due to the formation of a rubber/ black network. But, reduce tensile rate can decrease the N115 content for reinforcing NR with all possible cut sizes. This is noted as a second turning point of black concentration.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Polymer Science

Grantor dc:publisher

University of Akron

Year dc:date

2013

Author dc:creator

• Wang, Qinwei

Contributors dc:contributor

• Hamed, Gary

• Polymers

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=akron1365778539

OAI identifier oai:identifier

oai:etd.ohiolink.edu:akron1365778539