Addition Of High-density Polyethylene Research Articles

IPP/HDPE blends. II. Modification with EPDM and EVA

Past work has shown that addition of high-density polyethylene (HDPE) to polypropylene (PP) resulted in a significant reduction in the elongation at break and in the gate-region impact strength of injection molded articles. In this study, we report on the compatibilization of these blends with ethylene/propylene/diene monomer (EPDM) or ethylene/vinyl acetate (EVA) copolymers. EPDM is effective at improving the impact strength and gate puncture resistance of a 90/10 PP/HDPE blend. EVA, on the other hand, is effective at improving the impact strength and the elongation at break of this material. It was also found that EVA is a better impact modifier for PP than is EPDM. DSC analysis indicated that EPDM, when blended with PP, caused a significant reduction in the degree of crystallinity of the PP. This was not observed in the case of EVA/PP blends. Further, our results indicate that care must be taken in designating a particular material as a better compatibilizer than some other material. It is crucial that conditions be attached to the label compatibilizer, indicating in particular the desired mechanical properties of the blend. © 1996 John Wiley & Sons, Inc.

IPP/HDPE blends. II. Modification with EPDM and EVA

Past work has shown that addition of high-density polyethylene (HDPE) to polypropylene (PP) resulted in a significant reduction in the elongation at break and in the gate-region impact strength of injection molded articles. In this study, we report on the compatibilization of these blends with ethylene/propylene/diene monomer (EPDM) or ethylene/vinyl acetate (EVA) copolymers. EPDM is effective at improving the impact strength and gate puncture resistance of a 90/10 PP/HDPE blend. EVA, on the other hand, is effective at improving the impact strength and the elongation at break of this material. It was also found that EVA is a better impact modifier for PP than is EPDM. DSC analysis indicated that EPDM, when blended with PP, caused a significant reduction in the degree of crystallinity of the PP. This was not observed in the case of EVA/PP blends. Further, our results indicate that care must be taken in designating a particular material as a better compatibilizer than some other material. It is crucial that conditions be attached to the label compatibilizer, indicating in particular the desired mechanical properties of the blend. © 1996 John Wiley & Sons, Inc.

IPP/HDPE blends: Interactions at lower HDPE contents

AbstractMechanical and rheological properties of blends of polypropylene (PP) and linear polyethylene (PE) were studied, with particular attention to the effects of aging of such mixtures. These two olefin polymers are basically incompatible. In PP‐rich blends, addition of highdensity PE (HDPE) causes only a slight decrease in tensile properties and impact resistance of injection‐molded specimens. In all cases, annealed specimens have higher moduli and lower impact strength than as‐molded products. While none of these changes are very drastic, the addition of small amounts of HDPE was observed to result in a serious decrease of gate‐region impact resistance of thin‐walled moldings. Blends with 10–20% HDPE exhibited an unexpected interaction in tensile, thermal, and melt‐flow properties as well as in crystallization behavior. © 1995 John Wiley & Sons, Inc.

Scanning electron microscopic studies on the tear fracture of polyethylene filled natural rubber vulcanizate

Tear failure of natural rubber (NR) filled with high density polyethylene (HDPE) was studied by scanning electron microscopy (SEM). The tear strength of NR was increased by the addition of HDPE. It was found that HDPE forms physical links with NR. The retention of tear strength by ageing attains an optimum value with HDPE loading.