Polypropylene-talc systems

Figure 12.4 Polypropylene-talc systems coveringa wide range of stiffness/toughness properties [28]. (With permission from the publisher.)...

Headlamp assemblies basically consist of two parts a transparent cover shield and body. The cover shield is generally made of polycarbonate (PC), which is scratch-protected by a hard coat e.g. by a UV-cured coating system. The body is generally polypropylene (PP) which is modified with fillers like talc. Headlamp... 

Borden KA, Weil RC, Manganaro CR. Optimizing properties of talc-filled polypropylene systems with a polymeric coupling agent. AN-TEC 1994 52(3) 2761. 

Surface treatment of caldte with stearic acid significantly reduces the viscosities and yield values of molten polymer compounds [4,5]. Small CaCOj particles are commercially treated with stearic add to improve their processability. Suetsugu and White [5] have investigated stearic acid effects on a calcite-filled system. They found an increasing order of reduction with decreasing particle size and decreasing shear rate. K. J. Kim and White studied the effect of stearic add on caldte and on talc particles in a polypropylene (PP) matrix [9 to 11 ]. 

A multilayer coextrusion die was used to create polypropylene (PP) / organoclay nanocomposites and to study the stress effects on clay dispersion. Nanocomposites contained 5 wt% maleic anhydride grafted PP compafibilizer and 1-5 wt% organoclay. Nanocomposite layers were extruded opposite talc fill PS before being separated. Individual PP nanoconposite layers were tested for improvements in mechanical, thermal and barrier properties and were compared to theoretical predictions in order to determine an aspect ratio for the organoclay. Aspect ratios from theory were compared to those measured directly through TEM. A PP nanocomposite / elastomer system was also considered. 

---