Nomenclature of Interpenetrating Polymer Networks

Full interpenetrating networks (IPNs) and semi-IPNs of Novolac (phenolic) resin and poly(ethyl methacrylate) (PEMA) were prepared by the sequential mode of synthesis. These were characterized with respect to their mechanical properties, that is, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Thermal properties were studied by DSC and thermogravimetric analysis (TGA). The morphological features were studied through polarizing light microscopy (PLM). The effects of variation of the blend ratios on the abovementioned properties were examined. There was a gradual decrease of modulus and UTS with consequent increases in elongation at break and toughness for both types of IPNs with increasing proportions of PEMA. An inward shift and lowering (with respect to pure phenolic resin) of the glasstransition temperatures of the IPNs with increasing proportions of PEMA were observed, thus indicating a plasticizing influence of PEMA on the rigid and brittle matrix of crosslinked phenolic resin. The TGA thermograms exhibit two-step degradation patterns. Although there was an apparent increase in thermal stability at the initial stages, particularly at lower temperatures, a substantial decrease in thermal stability was observed in the regions of higher temperatures. The surface morphology as revealed by PLM clearly indicates two-phase structures in all the full and semi-IPNs, irrespective of PEMA content. The matrix-PEMA domain interfaces are quite sharp at higher concentrations of PEMA.

Section: Introductionmentioning

confidence: 99%

Novolac resin–poly(ethyl methacrylate) interpenetrating polymer networks: Morphology and mechanical and thermal properties

Chakrabarty

Das

Roy

2003

“…Currently, products derived from IPNs find applications include false teeth to ion‐exchange resins, adhesives, high impact plastics, thermoplastics, vibration‐damping materials (for outdoor, aircraft, and machinery applications), high temperature alloys and medical devices . Based on the method of synthesis, IPNs can be classified into the following three categories: (A) Latex IPNs (LIPNs) whereby the formation of the interpenetrating networks is achieved by emulsion polymerization; (B) simultaneous interpenetrating networks whereby the first polymer is mixed with a monomer of a second polymer along with the initiator and a crosslinking agent allowing it to polymerize and crosslink inside the swollen first polymer; and (C) sequential IPN whereby two polymers are mixed either in a solution or in the bulk and then crosslinked in presence of each other …”

Section: Introductionmentioning

confidence: 99%

Biobased interpenetrating polymers networks derived from oligomerized soybean oil and polydimethylsiloxane

Dewasthale

Graiver

Narayan

2014

A series of interpenetrating polymer networks (IPNs) with different compositions were prepared from silylated oligomerized soybean oil and silanol-terminated polydimethylsiloxane. Oligomerization of soybean oil was achieved by heating it with a catalyst in a Parr reactor at elevated temperatures. Vinyltrimethoxysilane was then grafted onto the oligomerized oil. Crosslinked films were obtained from solutions as the silanol groups between the two immiscible components condensed to form stable siloxanes linkages resulting in an entangled network characterized by microphase separation typical to IPNs. The crosslink density between the dispersed phase and the continuous phase was calculated from the average particle size of the dispersed phase. The mechanical and thermal properties were also studied and were found to be directly related to the composition and the crosslink density. These IPN resins can be used as high release liners, low friction materials, soft-feel coatings or as convenient one-package protective coatings.

“…Due to the interlocking configuration, properties of IPNs are not influenced by subsequent aging rather these are frozen‐in 6. Generally, the component present in higher concentration and with lower viscosity, is supposed to form the continuous phase, which dictates the ultimate properties 7. Moreover, systems with both components crosslinked (full IPNs) tend to develop two continuous phases.…”

Section: Introductionmentioning

confidence: 99%

Sequential interpenetrating polymer networks of novolac resin and poly(2‐ethyl hexyl acrylate)—thermal, mechanical, and morphological study

Goswami

Maji

2011

Interpenetrating polymer networks (IPN) of novolac/poly (2-ethyl hexyl acrylate) (PEHA) have been prepared via in situ sequential technique of IPN formation. Full and semi-IPNs were prepared with different blend ratios (w/w) e.g., 90 : 10, 80 : 20, and 70 : 30 in which the major constituent was novolac resin. A gradual decrease in specific gravity and hardness values was observed with increase in PEHA incorporation. A steady decrease in crosslink density with increase in PEHA fraction in the IPNs was quite evident. The IPNs were characterized with respect to their mechanical properties, e.g., ultimate tensile strength, percentage elongation at break, modulus, and toughness. Thermal behavior was studied by differential scanning calorimetry and thermogravimetric analysis. A plasticizing influence of PEHA on the rigid, brittle, and hard matrix of crosslinked phenolic resin is evidenced from the mechanical and thermal properties. The twophase surface morphology is revealed by scanning electron microscope.