| 1. |
- Bengtsson, Magnus, et al.
(författare)
-
Extrusion and mechanical properties of highly filled cellulose fibre-polypropylene composites
- 2007
-
Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier BV. - 1359-835X .- 1878-5840. ; 38:8, s. 1922-1931
-
Tidskriftsartikel (refereegranskat)abstract
- This study focused on manufacturing of highly filled cellulose fibre-polypropylene composites and evaluation of the mechanical properties of the composites. Cellulose fibre reinforced polypropylene composites with up to 60 wt-% of fibres with and without coupling agent were manufactured by extrusion. In order to achieve consistent feeding of the fibres into the extruder a pelletization technique was used where the fibres were pressed into pellets. Two commercial grades of cellulose fibres were used in the study, bleached sulfite and bleached kraft fibres. Fibre dimension measurements showed that the pelletization process and extrusion at high fibre loading caused the most severe fibre breakage. Flexural testing showed that increased fibre loading made the composites stiffer but reduced the toughness. Addition of maleic anhydride grafted coupling agent increased the stiffness and strength of the composites significantly. In general, there was no significant difference in the mechanical properties between the composites with kraft and sulfite fibres. Scanning electron microscopy showed that addition of coupling agent improved the interfacial adhesion between the fibres and polypropylene matrix.
|
|
| 2. |
- LeBaillif, Marie, et al.
(författare)
-
Challenges in processing of cellulose fiber polyolefin composites
- 2007
-
Konferensbidrag (refereegranskat)abstract
- The interest to use cellulose fibres as reinforcement in polyolefin polymers started since middle of 1980, mainly because of the good mechanical properties, low cost and abundance of cellulose fibres. The most studies have been focussed on the adhesion problem between hydrophilic cellulose and hydrophobic polymers and not on the processing of these materials. Therefore the compounding process of cellulose fibre polyolefin composites by extrusion is still a challenge. The main problems on the processing of the composites is the difficulty in handling of the cellulose fibres, the poor dispersion of the fibres into the polymer matrix, the thermal sensitivity of cellulose and the reduction of the fibre length. The goal of this study has been to understand how the nature of cellulose fibres and the process will affect the dispersion and aspect ratio of the fibres. Two different cellulose fibres were used, softwood and hardwood and the matrix was polypropylene (PP). The fibres were pelletized to be able to feed these into the extruder. The materials were compounded with a co-rotating twin screw extruder followed by compression moulding to test samples. The fibre content was fixed at 20 and 30 wt%. The composites flow properties and microstructures were studied in order to optimize the dispersion of the fibres in PP matrix. The fibermaster and image analysis were used to study how the fibre length was affected by the extrusion process.
|
|
| 3. |
|
|
