12 research outputs found
The efficiency of the Sudan-III-staining to identify wear particles of PMMA-bone cement in tissue after total endoprostheses
Comparison of different beta-nucleators for isotactic polypropylene, characterisation by DSC and temperature-modulated DSC (TMDSC) measurements
The nucleating efficiency and selectivity of different beta-nucleating
agents was characterised and compared by differential scanning
calorimetry, (DSC) and temperature-modulated DSC (TMDSC). The
nucleating agents were the calcium salts of pimelic and suberic acid
(Ca-pim and Ca-sub), linear trans-gamma-quinacridone (LTQ), a
commercial nucleator NJ Star (NJS) and an experimental product
(CGX-220). The efficiency and the selectivity of Ca-sub and Ca-pim are
extremely high. NJS is efficient above a critical concentration, which
is connected with its partial dissolution in polypropylene melt. LTQ
and CGX-220 possess strong overall nucleating ability and moderate
selectivity. Using TMDSC, we found that three consecutive processes
take place during the heating of beta-nucleated samples cooled down to
room temperature: reversible partial melting of the beta-form,
irreversible beta alpha- recrystallisation, and the melting of the
alpha-modification formed during beta alpha- recrystallisation or being
present in samples prepared with non-selective beta-nucleators. Melting
of the alpha-phase contains both reversible and irreversible components