New nanocomposites of polypropylene and carbon nitride with high thermal and mechanical performance obtained by melt processing techniques

Profil Titel	New nanocomposites of polypropylene and carbon nitride with high thermal and mechanical performance obtained by melt processing techniques
Referenz	10 ES 28G2 3JLT
Herkunftsland	Spain
Kooperationsart	Angebot
Eintrag/Änderung	2011-01-13 / 2012-11-07
Status	update

Kurzfassung

A Spanish public research organization has developed new polymer nanocomposites based on polypropylene and spherical carbon nitride nanoparticles using melt processing techniques. Carbon nitride nanoparticles do not require previous exfoliation or modification, and the use of low amount of nanoparticles allows the preparation of stronger and lighter materials with improved thermal and mechanical properties. Collaboration for further development and a license agreement are being sought.

Details

Research in polymer nanocomposites has grown substantially in recent years due to the need for lighter, stronger and better performing alternatives to conventional composites.
Among the most versatile polymer matrices are polyolefins such as polypropylene (PP). This thermoplastic polymer is very widely used because of its high availability in the market, its wide range of properties, and its low cost. In spite of all these advantages, PP has some deficiencies in mechanical properties for certain applications, like its low impact resistance at low temperatures, for example. However, the reinforcement of this kind of polymer with nanoparticles (e.g. PP/POSS (Hybrid Plastics), PP/nanoclays (General Motors Corp.), PP/Halloysite nanotubes (Naturalnano)) are limited by the solubility and distribution of the nanoparticles in the polymer matrix, which require costly exfoliation or modification methods
CSIC has patented a technology where carbon nitride nanoparticles are used for the preparation of new polypropylene nanocomposites in a single step. The process occurs in melt state by physical mixing of the polymer matrix with the nanoparticles by traditional melt-processing techniques (such as conforming, extrusion, compression or injection moulding) in one step. The polymer matrix can be any polyolefin, like e.g. polypropylene (homopolymer, copolymer, blend, etc.).
Thanks to their elliptical or spherical shape, synthesized carbon nitride (C3N4) particles are easier to mixture and disperse into the polymer matrix without prior exfoliation or modification. Moreover, C3N4 particles have a nucleating effect on polypropylene cristallization, and cause an increase of the cristallization temperature when their concentration is raised. (an increase of cristallization temperature of 6ºC is obtained in 2% weight compositions of nanoparticles) This produces an increase of polymeric matrix cristallization speed, causing a reduction of the processing cycle and, therefore, a costs reduction of the preparation process.
Due to the hardness of the carbon nitride nanoparticles, ultrahard and ultralight reinforcing materials can be formed with a very low amount of nanoparticles.
The viscoelastic modulus at room temperature is 1300MPa for PP pure and 1900 MPa for nanocompounds with 0,1% of C3N4 , that shows a very high increase of the matrix polymeric rigidity. The C3N4 particles presence also produces an increase of the Heat Deflection Temperature, HDT, that is the temperature at which a plastic sample deforms under a specified load. A nanocompound with 0,1% of C3N4 produces an increase of T1300 of Polypropylene pure of 16ºC.

Innovative Aspects:
The processing here reported of new formulations of polypropylene with carbon nitrides nanoparticles, include the following advantages:
- One-step process carried out by traditional melt processing techniques, viable for large scale applications.
- Carbon nitride nanoparticles do not require prior exfoliation or modification and are very well dispersed into the polypropylene matrix.
- Environmentally friendly procedure (not require organic solvents).
- Significantly shorter cycle times than conventional processes, reducing the cost of the process
- Nanocomposites obtained by this procedure have unique thermal and mechanical properties (low density, extreme hardness, wear resistance, chemical inertness, and biocompatibility).