The synthesis and complete characterisation of a new family of linear copolymers (LCP) has been carried out. LCPs act well as processing aids. Preliminary results on extruded or injection moulded samples indicate that it is possible to orient LCPs into transition processing (TP) matrices. In some cases, improved mechanical performance has been evident. A database has been set up and machines have been constructed to carry out the required processes.
Self reinforcing composites with relatively low viscosity are obtained by blending thermotropic liquid crystal polymers (LCP) and thermoplastic matrices (TP). These blends represent a convenient method for exploiting some of the outstanding properties of LCPs but at a reduced cost.
This project aimed to verify the possibility of employing LCPs, due to their fibrous morphology and low melt viscosity, both as reinforcing agents and processing aids of conventional TPs.
The main objectives have been completely fulfilled and also these intermediate objectives have been achieved:
synthesis and characterization of tailored structures of LCPs;
construction of segmented machines with different processing behaviour compared to other continous compounding machines;
investigation on how LCPs blends should be compounded for the obtainment of self reinforced composites;
complete characterization of blends properties;
set up of a central database.
As regards the results, both qualitative and quantitative information on processing aid effect of LCP have been obtained: viscosity of melt blends is constantly much lower than that of the TP alone and processing temperature is reduced: semirigid LCPs, when compounded with all types of TPs, give better results than fully aromatic LCPs.
The achievement of self reinforcing composites depends on the ability to melt process blends in such a way that LCPs form the reinforcing phase: in term of moduli the best performance has been obtained when a fully aromatic LCP is used while semirigid LCPs give better results in term of impact strength.
Many parameters which influence the reinforcing action have been completely understood and particularly the mutual influence of the LCP and TP structures: this aspect is innovative to the state of the art and is fundamental for the obtainment of self reinforcing composites.
The database provided major assistance for the large quantities of data that had to be processed and interpreted i n the course of the project.
THE AIM OF THE PROJECT IS TO VERIFY THE POSSIBILITY OF EMPLOYING LIQUID CRYSTAL POLYMERS (L.C.PS.) AS REINFORCING AGENTS OF CONVENTIONAL THERMOPLASTIC POLYMERS (T.PS.) AND, IF SO, TO COMPARE THE PERFORMANCES OF THE NEW MATERIALS WITH RESPECT TO THE ONES OBTAINED WITH TRADITIONAL CHOPPED GLASS FIBRE COMPOSITES.
THEREFORE, DIFFERENT T.PS. WILL BE COMPOUNDED WITH VARIOUS THERMOTROPIC AND NEMATIC COPOLYESTERS L.C.PS., COMPOUNDED BLENDS PROCESSED BY EXTRUSION AND THE RESULTS OBTAINED ON DIFFERENT MACHINES WILL BE COMPARED.
BOTH COMPOUNDED AND PROCESSED MATERIALS WILL BE TESTED FOR THEIR MECHANICAL AND PHYSICAL PROPERTIES.
THE EXPERIMENTAL RESULTS WILL BE EVALUATED IN COMPARISON WITH EXISTING REINFORCED AND NON REINFORCED MATERIALS. THIS TARGET IS EXPECTED TO BE ACHIEVED BY USING AN AD HOC CONSTRUCTION OF A MODEL EVALUATION SYSTEM.
THE MAIN FORESEEN ADVANTAGES ARE:
- THE POSSIBILITY OF CREATING REINFORCING SPECIES DURING THE COMPOUNDING, AS L.C.PS HAVE A FIBROUS MORPHOLOGY WHICH ALLOWS THE FORMATION OF FIBROUS INCLUSIONS IN THE T.PS.,
- THE POSSIBILITY OF OPERATING WITH MILD PROCESSING CONDITIONS BECAUSE OF THE LOW MELT VISCOSITY OF THERMOTROPIC AND NEMATIC L.C.PS.
Funding SchemeCSC - Cost-sharing contracts
32547 Bad Oeynhausen