Influence of filler on the polypropylene structure

Khünová, Viera; Šmatko, V.; Hudeč, Ivan; Beniska, J.

doi:10.1007/bfb0114372

Cited by 13 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values of n vary within the range of 2.5–2.9 for pure PP and 1.8–2.3 for composites, depending on the crystallization temperature and the talc type. According to previous studies, the fractional values of n can be assigned to different spatial growth of crystals, depending on their value 21. For PP, n is equal to or greater than 2.5 indicating that the dominant crystal morphology is spherulitic, as expected.…”

Section: Resultsmentioning

confidence: 74%

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Castillo

Barbosa

Capiati

2012

J of Applied Polymer Sci

View full text Add to dashboard Cite

Talc is a laminar silicate, considered as an excellent nucleating agent for polypropylene (PP) crystallization. However, properties of PP/talc composites depend on the morphology, size, and surface of mineral particles. In this sense, talc from several ores, having different morphology, imparts specific characteristics on these materials. Also, taking into account that PP-talc adhesion is not necessarily good due to the apolar character of PP, talc surface has been modified in order to increase this parameter. In this work, the effects of talc genesis, geomorphologic aspects, and particle surface characteristics on crystallization of PP/talc composites are analyzed. Isothermal crystallization of PP/talc composites was studied by using differential scanning calorimetry, based on Avrami model. The final crystalline morphology of talc-filled PP was analyzed by means optical microscopy. The results show that the blocky talc morphology favors even more the crystallization compared to the platy one, at the same particle size. Taking into account the surface treatment studied in this work, the talc surface is made hydrophobic and the particle delamination is favored. As a consequence, so-modified talc is very effective in increasing the crystallization temperature of PP and the nuclei number that grow during the crystallization with respect to the untreated talc.

show abstract

Section: Resultsmentioning

confidence: 74%

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Castillo

Barbosa

Capiati

2012

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Even the T c and T m of powdered PP filled with Al(OH) 3 are higher than those of pelletized PP filled with Al(OH) 3 . It is well known that many fillers are heterogeneous nucleating agents for PP, influencing not only its temperature and degree of crystallization, but also the nature of the micromorphology in the crystalline phase 36, 37. It is suggested that Al(OH) 3 /PP composites prepared by powdered PP more significantly improved the filler dispersion in the matrix.…”

Section: Resultsmentioning

confidence: 99%

Physical and mechanical properties of Al(OH)₃/polypropylene composites modified by in situ‐functionalized polypropylene

Mai¹,

Li²,

Qiu³

et al. 2002

J of Applied Polymer Sci

View full text Add to dashboard Cite

Al(OH) 3 /polypropylene (PP) composites modified by in situ-functionalized polypropylene (FPP) were prepared by a one-step melt-extrusion process. The effect of in situ FPP on the crystallization and melting behavior, melt-flow index, limiting oxygen index, thermal degradation, mechanical properties, and fracture morphology of Al(OH) 3 /PP composites was studied. Formation of in situ FPP resulted in a decreased crystallization temperature and melting point of PP in the composites, an increased melt-flow index, and improved tensile and flexural strengths of Al(OH) 3 /PP composites, whereas the thermal degradation behavior and limiting oxygen index was not been influenced. The impact strength of the Al(OH) 3 /PP composites modified by in situ FPP depended upon the content of the initiator, dicumyl peroxide, and the monomer, acrylic acid.

show abstract

“…The presence of a crystalline phase in the PP matrix creates astructure similar to at wo-phase blend with one phase crystalline and the other amorphous (Nielsen and Landel, 1993). Some nanotubes may act as nucleating agents for the start of non-isothermal crystallization during cooling but most of them are expected to be found only in the amorphous phase since from the thermodynamic point of view fillers and other impurities cannot exist in acrystal as they interfere with the ordering process (Sharples, 1966;Khunová et al, 1988;Nordmark and Ziegler, 2002). In their demonstration of spherulitic crystallization from polypropylene melts, Keith and Padden (1964) show that molecules of low molecular weight considered as \ impurities" are rejected preferentially by the growing crystals in asegregation process and may play amajor role in determining the crystalline structure.…”

Section: Morphologymentioning

confidence: 99%

“…However, PP exhibits avery poor compatibility and low adhesion towards other materials and inorganic fillers owing to its non-polarity and absence of functional groups. It has been found that in PP/clay nanocomposites, crystallization of the PP matrix led to clay platelets expulsion from the crystalline phase by thermodynamic forces (Khunová et al, 1988). Breuer et al (1998) studied the effect of shear rate on electrical resistivity of HIPS/LLDPE/CB extrudates produced by ac apillary rheometer and found that it was more sensitive to shear rate for single matrix composites than for blend composites and that, in most cases, the resistivity increased with shear rate.We also previously showed that high degrees of nanotube alignment in the flow direction resulted in asignificantincrease in the electrical percolation threshold of polycarbonate (PC)-MWCNT nanocomposites (Abbasi et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Carbon Nanotube Conductive Networks through the Double Percolation Concept in Polymer Systems

Abbasi

Derdouri

Carreau

2014

International Polymer Processing

View full text Add to dashboard Cite

We investigated the electrical conductivity and percolation behavior of binary and ternary nanocomposites based on multiwalled carbon nanotubes (MWCNs) using polypropylene (PP) and ab lend of PP with cyclic butylene terephthalate (CBT). The nanocomposites were prepared by diluting acommercial 20 %wtMWCNT PP masterbatch using optimized melt-mixing conditions. The concentration of carbon nanotubes in the diluted PP samples was as low as 0.5 %a nd as high as 15 %i nw eight. For the PP/CBT blend CBT concentration was varied up to 40 %wt while the loading of CNT was from 0t o5%wt. SEM and TEM techniques were used to examine the quality of the dispersion and the formation of nanotube networks within the polymer matrix. TEM and Raman spectroscopy results showed that for the diluted PP/MWCNT composites the nanotubes are well aligned in samples obtained the microinjection molding process, although the level of alignment is less with crystalline PP than in an amorphous matrix such as polycarbonate (PC). FTIR and XRD results revealed that the orientation of both polymer chains and crystals decreasedw ith the incorporation of nanotubes into PP. The electrical conductivity was also significantly altered by the nanotube alignment in aPPmatrix, as was previously observed for PC/MWCNT composites; the conductivity decreased and the percolation threshold rose in highly sheared samples; however, the presence of ac rystalline phase improved the conductivity even for high shear conditions through the phenomenon of double percolation threshold. This last concept refers to the requirement that the filler-rich phase be continuous and conductive and not to the existence of two percolation thresholds at two different CNT concentrations. The electrical conductivity of PP/CBT blends was also improved through ad ouble percolation that is the basic requirement for the conductivity of the ternary nanocomposites.

show abstract

Influence of filler on the polypropylene structure

Cited by 13 publications

References 0 publications

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Physical and mechanical properties of Al(OH)₃/polypropylene composites modified by in situ‐functionalized polypropylene

Carbon Nanotube Conductive Networks through the Double Percolation Concept in Polymer Systems

Contact Info

Product

Resources

About

Influence of filler on the polypropylene structure

Cited by 13 publications

References 0 publications

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Physical and mechanical properties of Al(OH)3/polypropylene composites modified by in situ‐functionalized polypropylene

Carbon Nanotube Conductive Networks through the Double Percolation Concept in Polymer Systems

Contact Info

Product

Resources

About

Physical and mechanical properties of Al(OH)₃/polypropylene composites modified by in situ‐functionalized polypropylene