Polybutadiene/polystyrene interpenetrating polymer networks

Abstract

Interpenetrating polymer networks (IPN's) of polybutadiene (PB) and polystyrene (PS) were prepared using both random (containing 36% cis, 55% trans, and 9% 1,2 vinyl) PB and high‐cis PB. For both series, a wide range of PB/PS compositions were synthesized. Using samples stained with osmium tetroxide, electron microscope studies revealed an irregular cellular structure of a few hundred Ångstrom diameter with the first component, PB, making up the cell walls. The size of the cells was found to depend on the PB crosslink density for the random materials. Modulus‐temperature data revealed two distinct glass transitions, confirming the microscopy finding of two phases. However, the transition temperature and transition slope varied with composition, and with the microstructure of the polybutadiene, giving evidence of significant molecular mixing. Stress‐strain data on the IPN's showed that materials rich in PB behave like self‐reinforced elastomers. Charpy impact resistance experiments on materials rich in PS indicated values of 5 ft‐lb/in. of notch, which compares well with graft‐type polyblends of similar PB/PS composition. The results were interpreted in the light of the recent theoretical work of Bragaw, who considered the importance of the distances between domain boundaries with respect to crack acceleration mechanics. Although the IPN's considered herein exhibited somewhat less than the predicted optimum phase dimensions, the arrangement of the domains is different from ordinary impact resistant plastics.

Studies on the thermal characteristics of polymer alloys

“…This has important technological implications, as chemical, physical and mechanical properties, as well as appearance, all depend upon composition uniformity. In fact, it is known [2][3][4] that these alloys very often exhibit a synergism in properties achievable only through this technique. Blending methods usually [5] involve solid -to -liquid, solid -to -solid or liquid -to -liquid mixing.…”

A semiempirical derivation of phase domain size in interpenetrating polymer networks

“…The cellular structure of sequentially synthesized IPN's has been well established. [6][7][8] A typical cellular structure for an SBR/PS IPN is shown in Figure 1. In this transmission electron micrograph, the diene-containing phase has been stained with osmium tetroxide.…”

Nomenclature of Interpenetrating Polymer Networks

“…N THE PAST five years, several investigators [1][2][3][4][5][6][7][8][9][10][11][12][13] have been studying a parIticular type of polymer blend in which various degrees of chain entanglement (depending on the polymers used and the method of blending) have been stabilized by homocrosslinking of the two polymers. In this manner, interpenetrating polymer networks (IPN) have been produced.…”

“…In this manner, interpenetrating polymer networks (IPN) have been produced. They have been shown to possess interesting properties and varying morphologies [1][2][3][4][5][6][7][8][9][10][11][12][13] .Because of the different methods of synthesis and varying compatibilities of the individual polymers, blends with different microstructures have resulted. It is the purpose of this paper to name these various structures according to their morphology and topology, as well as their method of syntheses.…”