Common industrial procedures often expose polymers to liquids and vapors which may affect their thermal properties. By carrying
out thermoanalytical measurements under simulated process conditions, the scientist can investigate environmental effects
on the properties of the material. Such experiments can also be used to demonstrate the nature of processes taking place.
This work illustrates case studies regarding the application of thermogravimetry, thermomechanical, dynamic mechanical and
dielectric measurements to monitor the behaviour of fibers, films and adhesives under such conditions.
The application of modulated temperature programs to thermomechanical analysis can be used to separate the reversible nature
of thermal expansion from irreversible deformation arising from creep under the applied load or changes in dimensions due
to relaxation of orientation. The effect of experimental variables and calibration are described. Modulated temperature TMA
allows the time-dependent nature of thermal expansivity to be studied. Measurements made under compression afford a means
of measuring the thermal expansivity of soft specimens independently of initial load. Application of these principles to scanning
thermal microscopy leads to a novel method of generating image contrast based upon local changes thermal expansivity of a
By employing a ‘modulated-temperature’ heating programme composed of a series of heat-isotherm stages, it is possible to separate
the change in dimensions of an oriented material during heating into two contributions: a thermally ‘reversing’ component
which is due to linear thermal expansion and a ‘non-reversing’ part arising from relaxation to the disordered state on heating
aboveTg. Some preliminary results for biaxially drawn poly(ethylene terephthalate) film are presented.
A procedure for calibrating the temperature scale of a DSC is described. A different calibration trend was obtained using
the transition points of organic compounds compared to that found using the melting points of highly pure metals. The crystal-crystal
transitions of three ammonium salts were studied by this method; ammonium dihydrogen phosphate and ammonium sulphate were
found to be suitable reference materials in the region −150 to 0°C, but ammonium nitrate was found to be unsuitable due to
poorly defined transition points and inconsistent thermal behaviour.
There is considerable interest in performing volatilisation and evaporation measurements by thermogravimetry. A quick and
simple method for determining vapour pressure using a conventional thermobalance and standard sample holders has been developed.
These yield meaningful thermodynamic parameters such as the enthalpies of sublimation and vaporisation. Under favourable conditions
the melting temperature and enthalpy of fusion of such compounds can be obtained. This technique has been used for the study
of dyes, UV absorbers and plasticisers. The use of modulated- temperature programs for such work is also described.
A method is explained for analysing matrices of statistics where each element should be approximately proportional to some column coefficient and also to some row coefficient. Using U. S. patent data as an example it is shown that entries are usually proportional to country size and patent category size. Deviations from proportionality expectations when tabulated often suggest policy implications.
International data show that the scientific development of the United States is neither better nor worse than expected for its size and industry. Its position is, however, deteriorating rapidly. The postwar expansion in federal funding of research seems to be a response to continued exponential growth rather than a cause. The science indicators volumes, all criticism notwithstanding, are rapidly provoking new understanding of these questions of scientific and technological change.
A method is explained for analysing square matrices of statistics giving transactions between each member of a set of nations, papers, journals, etc. In general self-transactions are different in kind to other exchanges of money, citations, etc., and a special method is given to compute row and column coefficients without relying on the diagonal elements. It is shown that this method yields very satisfactory analyses for journal and national citation data, enabling the members of the set to be assigned measures of size, quality and self-interest and a fuzzy set of clustered members from which all data may be derived.