A series ofcycloolefin copolymers (COCs) comprised of ethylene and norbornene units were characterized by NMR, W AXD, and DSC. The investigated compositional range was from 35.6 to 79.0 mol % ofnorbornene. Materials ofnorbornene content ofless than 50 mol % were found to contain blocks of ethylene units and also sequences of alternating ethylene/norbornene units. In these cases the stereoregularity of the chain was relatively high. Materials of norbornene content of more than 50 mol % were also found to contain alternating sequences but additionally showed components of a more random nature including blocks of norbornene units of varying lengths. The stereoregularity of the chain was relatively low in these cases. Differences in the WAXD of the materials were related to these differences in chemical architecture. All the materials showed one Tg which varied linearly with the composition of the copolymer.
A well-defined modification of poly(tetrahydr0furan)s was realized by grafting with maleic anhydride. The grafted products were investigated by Fourier-transform infrared (FTIR) spectroscopy and l3C nuclear magnetic resonance (NMR) spectroscopy. FTIR spectroscopy evidenced a characteristic shift of the carbonyl valence vibrations of cyclic anhydrides to higher wave numbers due to grafting. The grafting of maleic anhydride, which occurred mainly onto poly(tetrahydr0furan) carbons in a-position, was proved by means of I3C NMR spectroscopy. Furthermore, it was found that approximately 10% of all graftings took place onto poly(tetrahydr0furan) carbons in P-position. All the grafted units were monosubstituted succinic anhydride units. Indications for the formation of poly(ma1eic anhydride) graft units were not found. The quantitative determination of grafted anhydride units was carried out by titration after hydrolysis to the acid form. Remarkably high values of percentage grafting up to 20 wt.-Vo of maleic anhydride were obtained using an initiator concentration of only 2.5 mol-Vo related to maleic anhydride. The high values of percentage grafting at an initial maleic anhydride concentration of 20 wt.-Yo were due to a nearly complete conversion of the maleic anhydride. If the initial amount of maleic anhydride was higher than 20 wt.-Vo phase separation took place during the reaction. This phase separation prevented complete conversion of the maleic anhydride.
The dependence of the morphology development of physical as well as of reactive compatibilized polypropylene/polyamide 6 (PP/PA6) blends in a mixing zone of a co‐rotating twin screw extruder on blend composition and screw rotational speed was investigated. A special process analytical set‐up based on a co‐rotating twin screw extruder was used, which allowed melt sampling from different positions along the operating extruder in time periods less than 10 seconds. It has been shown that the disperse particle sizes in physical blends depend crucially on the blend composition because of the increasing influence of coalescence with an increasing concentration of the disperse phase. Furthermore, the morphology of physical PP/PA6 blends depends strongly on their rheological properties. In contrast, the influence of the screw rotational speed on the morphology is minor. The resulting particle size in a mixing zone is achieved already after a short screw length. The particle size of compatibilized blends is significantly smaller than in physical blends because of the better conditions for drop break‐up and the suppression of coalescence effects. Due to this, compatibilization has a stronger influence on the blend morphology than a variation of process or rheological conditions with physical blends. Furthermore, the compatibilization leads to a concurrent crystallization of the PA6 phase with the PP phase.
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