Studies of the effect of titanate coupling agent on the performance of polypropylene–calcium carbonate composite

ABSTRACT:The melt rheological behavior of calcium silicate-filled isotactic polypropylene, with filler volume contents of 0 -17.8%, was determined at 493 K. The composites followed the power law in shear stress versus shear rate variations and were shear thinning. Initially, apparent melt viscosity decreased until a critical filler volume content of 8.5% was reached. However, on further increase in calcium silicate concentration, apparent melt viscosity increased. Melt elasticity also showed an initial decrease until 8.5% filler content was reached and then an increase beyond this filler content. Surface treatment of calcium silicate with a titanate coupling agent, LICA 38, modified the rheological properties because of the plasticizing/lubricating effect of LICA 38.

Section: Apparent Melt Viscosity ( App )mentioning

confidence: 94%

Rheological properties of calcium silicate‐filled isotactic polypropylene

Maiti

Singh

Ibrahim

2002

“…Silane and titanate types of coupling agents have been gaining importance in recent time, and many claims and counterclaims have been made about its efficacy. Sharma et al 11 in their article on the effect of a titanate coupling agent on the performance of CaCO 3 -filled PP showed that upon the treatment of the filler with an isopropoxy triisostearoyl titanate coupling agent, a 20% improvement in the impact strength was recorded, whereas the elongation at break of the composite was slightly less than that of virgin PP. They also claimed that this increase in the impact strength was not as evident as reported by Han et al, 12 who also worked on PP/CaCO 3 systems previously, even though the fillers were also treated with titanate coupling agents.…”

Section: Introductionmentioning

confidence: 95%

Effects of filler treatments on the mechanical, flow, thermal, and morphological properties of talc and calcium carbonate filled polypropylene hybrid composites

Leong

Bakar

Ishak

et al. 2005

ABSTRACT:Commercially available neoalkoxy titanate (Lica 12) and organosilane (3-aminopropyltriethoxysilane) coupling agents were used to treat talc and calcium carbonate (CaCO 3 ) to compare their effects with those of untreated fillers upon their incorporation into polypropylene (PP). Commercial stearic acid treated CaCO 3 was also used to widen the scope of the study. Single-filler PP composites (containing either talc or CaCO 3 ) and hybrid-filler composites (containing a mixture of talc and CaCO 3 ) were compounded on a twin-screw extruder and subsequently injection-molded into dumbbells. The silane and titanate treatments dramatically increased the elongation at break for both the single-filler and hybrid-filler composites, whereas stearic acid did not. There was also a moderate improvement in the impact strength of the composites, particularly those treated with Lica 12. The hybrid composites, through the synergistic coalescence of positive characteristics from talc and CaCO 3 , had exceptionally good impact properties, more so with the aid of the coupling agents. For example, the impact strength value of a Lica 12 treated hybrid composite was the greatest for all the composites studied, overshadowing the superiority of the CaCO 3 -filled PP composites, which predominantly had the highest impact properties. Further investigations of the thermal and morphological properties were also conducted to facilitate the determination of the coupling mechanisms and their interesting effects on the hybrid composites.

“…As nCaCO 3 does not exhibit good adhesion and dispersion in a matrix of PP, various surface treatments have been applied. 4,5 Much research has been reported about the surface modification of nCaCO 3 6,7 and the effects of modified nCaCO 3 on the properties of PP. 8 The most widely used methods of surface modification are surface grafting and coupling, such as the grafting of unsaturated carboxylic acids and the coupling of titanates, aluminates, phosphates, and zirconates.…”

Section: Introductionmentioning

confidence: 99%

Effects of nano calcium carbonate modified by a lanthanum compound on the properties of polypropylene

Guo

Wang

Zhang

et al. 2005

ABSTRACT:The surface modification of nano calcium carbonate (nCaCO 3 ) particles was carried out with a soluble compound of lanthanum via a coating process of chemical deposition, and nCaCO 3 particles covered with a compound of lanthanum (nCaCO 3 -La) were prepared. The polypropylene (PP)/nCaCO 3 and PP/nCaCO 3 -La composites were prepared with a two-roll mill. The measurements of the mechanical properties showed that the impact strength of the composites increased at first and then decreased with the addition of fillers, and the tensile strength was reduced at the same time. The impact strength of PP/nCaCO 3 -La was higher than that of PP/nCaCO 3 , and the impact strength of PP/nCaCO 3 -5La was three times that of virgin PP. Transmission electron microscopy and scanning electron microscopy showed that nCaCO 3 -La dispersed well in the PP matrix, the size distribution of the particles was uniform, and nCaCO 3 -La adhered to the PP matrix very closely. The crystallization properties of virgin PP and its composites were studied with differential scanning calorimetry and wide-angle X-ray diffraction. The results showed that the ␤-PP phase easily formed with the addition of the lanthanum compound. In comparison with virgin PP, the addition of nCaCO 3 -La led to a higher crystallization temperature. The size of the crystallites increased with the addition of nCaCO 3 -La, and the nucleation of PP crystalline was also improved.