Hardness of weakly and late crosslinked polystyrene and its relation to chain statistics

DETERMINATION OF THE RELAXATION SPECTRUM FROM OSCILLATORY SHEAR DATA ORBEY, N; DEALY, JM (1991-08-01) In order to use either a linear or nonlinear model of viscoelasticity to calculate the stress response of a material to various deformations, it is usually necessary to have available an explicit equation for the linear relaxation modulus G(t). The most popular procedure is to use the data from a small-amplitude oscillatory shear experiment to determine the parameters of a generalized Maxwell model. However, this is an ill-posed problem and is not at all a straightforward curve-fitting operation. We comp...
Preparation and characterization of thermally stable organoclays and their use in polymer based nanocomposites Abdallah, Wissam; Yılmazer, Ülkü; Department of Chemical Engineering (2010) The present study was aimed at exploring the purification and modification of montmorillonite rich Turkish bentonites by organic salts and their subsequent effects on the morphology (X-diffractometry, transmission electron microscopy, scanning electron microscopy), melt flow index, mechanical (Tensile, Impact) and especially thermal stability (thermal gravimetric analysis, differential scanning calorimetry) properties of polymer/organoclay nanocomposites with and without an elastomeric compatibilizer. The b...
Preparation and characterization of acrylic bone cements Endoğan, Tuğba; Hasırcı, Nesrin; Department of Chemistry (2005) Acrylic bone cements are used in dentistry and orthopedic surgery to fix prosthetic devices into the bone. Bone cements transfer and distribute the applied load and increase the load-carrying capacity of the prosthesis/cement/bone system with the help of mechanical bonding between the device and the bone. In spite of all their advantages, bone cements have several drawbacks such as insufficient mechanical properties, high exothermic polymerization temperature, release of monomer to the environmental tissue ...
Synthesis and characterization of polystyrene clay nanocomposites Özden, Gülsüm; Yılmazer, Ülkü; Department of Chemical Engineering (2004) This study was undertaken to prepare polystyrene (PS)/montmorillonite (MMT) nanocomposites by different methods, including melt intercalation, in-situ polymerization and masterbatch methods. The in-situ polymerization method consisted of dispersing the styrene monomer into the galleries of MMT followed by subsequent polymerization. The PS/MMT nanocomposites formed by melt intercalation method were prepared on a twin-screw extruder. The masterbatch method was in fact a two-step process. As the first step, a ...
Effect of different compositions rheological and mechanical properties of epdm rubber Çavdar, Seda; Usanmaz, Ali; Department of Polymer Science and Technology (2007) In this work, EPDM rubber was compounded with increasing amount of filler (FEF N 550 type carbon black), process oil (saturated mineral oil), vulcanizing agent [di (t-butylperoxy) diisopropyl benzene, i.e., BBPIB] and diene [5-ethylidenebicyclo(2.2.1)-hept-2-ene, i.e., ENB] in order to investigate mechanical and rheological properties. Effect of Increasing amount of filler was investigated by using FEF N 550 type carbon black in 35, 70, 87.5, 105 phr. Decrease in scorch times of vulcanization reactions, ts2...

Citation Formats

M. M. H. Fares, “Hardness of weakly and late crosslinked polystyrene and its relation to chain statistics,” Ph.D. - Doctoral Program, Middle East Technical University, 1998.