Macroscopic stretching method

This requires little discussion since it is so well known. From the point of view of applications, it is by far the most important method. Strain 

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Spectra of Crystals Infrared Dichroism. The spectrum of a single crystal observed in polarized light depends upon the orientation of the crystal axes relative to the plane of polarization. A similar situation exists for macroscopically oriented high polymers, obtained by extruding or stretching polymeric materials such as nylon, polyvinyl alcohol, and polyethylene. Ellis and co-workers were the first to make systematic studies of IR dichroism in H bonded systems (604, 779, 780). Further attention was drawn to the method by Mann and Thompson (1334), Crooks (463), and Ambrose, Elliott, and Temple (595, 38, 589, 4). 

Tensile testing is done in a home-made [1] stretching-machine. The machine performs symmetric drawing in order to maintain the position of the beam on the sample. Signals from load cell and transducer are recorded during the experiment. The macroscopic deformation is determined close to the beam position to ensure accurate comparison of the mechanical data with the nanostructure evolution. For this reason a precise method has been developed [2]. In this method a pattern of fiducial marks is stamped on the sample. The sample is monitored by a TV-camera. Using the fiducial marks the local strain s = - o)/ o is computed automatically... 

A method has been developed recently to eliminate the thermal process for producing polyacetylene films. This technique is a liquid-crystal polymerization method, which allows oriented films to be prepared directly through an anisotropic reaction field (68-70). The field is produced by macroscopically orientated nematic liquid crystals, which are used as the polymerization solvent for a Ziegler-Natta catalyst. This technique yields highly oriented films in the trans configuration. This process produces polyacetylene with good conductivity (10 s/cm) without the need for thermal treatment and stretching, which causes defects and breaks fibrils in films. 

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