AbstractThe rubber elasticity characteristics of poly(n‐butyl acrylate) networks crosslinked with tetrafunctional (EGDM and TEGDM), hexafunctional (TMPTM), and octafunctional (PETMA) vinyl crosslinkers were investigated. Both gel—sol analyses and crosslinking efficiency theories were used to evaluate the chemical crosslink contributionvcand the entanglement contributionvpto the elastically effective network chainsve, and the effect of the crosslink junction functionalityfon the front factorg. The front factors obtained were in the range of 0.50–0.92, depending upon the network system and the counting method forvc.The relationship ofg= (f− 2)/f/〈r2〉/〈r2〉oseems reasonable in the case of the tetrafunctional and hexafunctional networks, but deviates in the case of the octafunctional network. It is also evident that the functionality scheme for the front factor could only be valid under the postulate of a highvp, which increases with increasingvc, especially in the highvcregion near the Gaussian limit. The average energetic contribution to the retractive force of the present systems, expressed asFe/F,
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