2,671 research outputs found

    Morphology and properties of polydimethylsiloxane-modified epoxy resin

    No full text
    The morphology and fracture toughness of epoxy resins modified with amino-terminated polydimethylsiloxane (ATPDMS), differing in their molecular weight, and the degree of the preliminary reaction in the melt state were investigated. Tetramethyl biphenol diglycidyl ether (TMBPDGE) was used as the base epoxy resin. The degree of preliminary reaction between epoxy and polysiloxane increased with the decrease of the molecular weight of polysiloxane in the melt state. When the low molecular weight polysiloxane (AT900) was mixed with high molecular weight polysiloxane in the preliminary reaction, the low molecular weight polysiloxane enhanced the compatibility between the epoxy resin and the high molecular weight polysiloxane and produced smaller size and narrow distribution of polysiloxane particles. The small and highly concentrated polysiloxane particles, as determined by scanning electron microscopy improved the fracture toughness of the epoxy resin. (C) 1997 John Wiley & Sons, Inc

    Physical aging of polydimethylsiloxane-modified epoxy resin

    No full text
    The thermal expansion coefficient and physical aging behavior of cured epoxy resins modified with amino-terminated polydimethylsiloxane were investigated. The epoxy resin was tetramethyl biphenol diglycidyl ether. Two factors influenced the thermal expansion behavior and the free volume relaxation of the polysiloxane-modified epoxy systems. One was the miscibility between the epoxy resin and the polysiloxane and the flexibility of the chains in the network system. The intrinsic thermal expansion of the network chains and the volume relaxation increased as a result of building polysiloxane molecules into the network structure. The other factor was the size and concentration of the dispersed polysiloxane particles. The increased local free volume at the interface between the epoxy matrix and the polysiloxane particle resulted in a higher thermal expansion coefficient and led to a large driving force for the volume relaxation during annealing. (C) 1998 John Wiley & Sons, Inc

    Siles, S.S., Letter to Mary Knight, September 20, 1863

    Full text link
    Stiles, S.S., Letter to Mary Knight, September 20, 1863. MS/52 William Knight Civil War Letters, Box 1, Folder 3. Valdosta State University Archives and Special Collections. 1 PDF and 2 scans. Includes transcript.The letter, dated September 20, 1863, is from Camp Lee and addressed to Mary. The author, identified as S.S. Siles, expresses relief that William has returned home and hopes for his quick recovery. Siles mentions the difficulties faced by women who visit camps to bring their sick husbands home, noting that officers rarely pay them any attention. Siles laments the poor condition of the tents, which are old and worn, failing to provide adequate shelter from rain. He mentions that the Quarter Master tried but failed to secure new tents in Savannah. The letter also touches on the precarious state of the Confederate army, suggesting that its future may hinge on an upcoming battle in Northern Georgia. Siles fears that a defeat could lead to mass desertions. The letter describes the men as being very sickly, attributing this to their poor diet of only beef and cornmeal. Siles himself is not in good health, suffering from chest pains and fevers, but continues to perform his duties as an acting Orderly Sergeant. He urges Mary to tell William to write to him and to keep him updated with news

    Declaration of Intention for Orazio Colletto

    No full text
    Declaration of Intention to become a citizen of the United States, as filled out and signed by Orazio Colletto. Applicant lists himself as a 58 year old farmer residing in Hammonton, New Jersey, born in Bordenaro, Italy on 17 January 1857, who sailed on the US bound vessel S.S. Prince. Declaration submitted and sworn June 3, 1915
    corecore