PS Network Research Articles

Optical implementation of 2-D perfect shuffle and folded perfect shuffle using speckle modulation

The perfect shuffle and the folded perfect shuffle are very useful and universal regular interconnections. An optical method using speckle modulation in the input plane and phase shift in the Fourier plane of a 4f system to implement an PS and FPS interconnection network is proposed. The experimental results show that this method is simple and feasible.

Sequential Interpenetrating Polymer Networks of Isotactic Polystyrene and Heterotactic Polystyrene

The synthesis and characterization of sequential interpenetrating polymer networks (SIPN's) of isotactic polystyrene and heterotactic polystyrene are reported in this paper. SIPN's with different cross-linking degrees or different compositions of isotactic PS networks show single Tg's in DSC thermograms, while in SEM micrographs the SIPN's exhibit a heterogeneous phase morphology.

Structure and properties of an interpenetrating polymer network-like system consisting of polystyrene-polyethylene: 1. Synthesis, elastomeric and thermoanalytical characterization

A polystyrene-polyethylene (PS-PE) interpenetrating polymer network (IPN)-like system was prepared by synthesis in situ. The system differs from ‘pure’ IPN systems in that the PS network is partially grafted onto the PE network. The mean molar mass of the polymer chain between two junction points ( M ̄ c ) was calculated from the values of uniaxial compression modulus. Differential scanning calorimetry and thermomechanical analysis measurements pointed to a considerable decrease of the crystalline phase in PE with increasing PS content. The melting temperature enhancement of the crystalline phase of PE is discussed.

Sequential interpenetrating polymer networks: heterogeneity of the first network and final structure

Various polystyrene/polybutadiene (PS/PB) interpenetrating polymer networks (IPNs) have been prepared by a sequential process. The first-formed network was obtained by radical copolymerization of styrene with divinylbenzene under various experimental conditions. Structural differences were obtained by varying the initial concentration of the solution when forming the network and/or the amount of crosslinker. Liquid PB was crosslinked within the PS network by a hydrosilylation reaction with chloroplatinic acid as catalyst. Transmission electron microscopy has shown that the two-phase morphology of the IPN cannot be attributed to the presence of imperfections in the tridimensional structure but can be related to the apparent swelling degree of the network formed first.

Data Requirements and Handshake for Thf CERN Antiproton Transfer Operations from the AA and PS to Client Machines

The CERN Antiproton Accumulator(AA) fulfils its role as a p- source for all the diverse needs at CERN ranging from a few 109 p-'s in a single bunch for the Low Energy Antiproton Ring(LEAR) every hour or so upto 1011 p-'s in 3 bunches for the Super Proton Synchrotron(SPS) Collider operations every 24 hours. The geographically dispersed accelerators involve large distances and proper synchronisation is mandatory for successful transfer operations. While every transfer operation needs preparatory work on all the machines involved in the chain with and without verbal communication in-between operators and control centres, an essential element has been the data exchange over the computer network linking the various processors in the PS and SPS Collider complex. This paper attempts to show some of the specialised data requirements which arose for the p- transfer operations and the essential software linking of various processes in different computers leading to a complete transfer operation from the AA, via the transfer lines and PS, to the SPS Collider or LEAR. For the Collider runs, the pre- and post-countdown data synchronisation and interchange involves upto a dozen computers in the PS and SPS computer networks.

Local concentration of units and molecular mobility in swollen polymer networks

An evaluation is made of the local concentration in a crosslinked network system based on the model of Gaussian subchains. The dependence of the local concentration on the location of the portion of the network studied, the closeness of crosslinking and the degree of swelling of the mesh is established. The authors compare the local concentration of the network and free branched and unbranched macromolecules in concentrated solutions at an identical concentration of the polymer. The effects of the inhomogeneity of real networks and their role in the experimentally observed fall in mobility with rise in the closeness of crosslinking found by the NMR method in swollen PS networks are discussed.

A comparative study of semi‐2 and full interpenetrating polymer networks based on poly(n‐butyl acrylate)/polystyrene

AbstractSequential poly(n‐butyl acrylate)/polystyrene (PnBA/PS) semi‐2 and full IPN's of various compositions were made by UV photopolymerization. Acrylic acid anhydride and divinylbenzene were used as labile and permanent crosslinkers, respectively, for the rubbery phase and the plastic phase. After IPN formation, network I was selectively decrosslinked. After extracton of polymer I, the remaining PS network II was characterized by swelling measurements and examined by scanning electron microscopy. It was found that crosslinked PnBA affects the formation of the second network more than uncrosslinked PnBA does. A porous phase formed by an aggregate of spherical polystyrene domains was observed. The experimental domain diameter was in good agreement with previous theoretical values. The dynamic mechanical properties of full IPN's, decrosslinked IPN's, and semi‐2 IPN's were also studied. A significant level of molecular mixing was found for full IPN's of midrange compositions. The major difference between the full IPN's and the decrosslinked IPN's is that the glass transitions of the respective polymers become more pronounced in the latter case, with a deeper valley between them. With the destruction of the crosslink sites, there is no longer a forced miscibility of the interlocked phases, which are, in fact, thermodynamically incompatible.