Roll-drawing and die-drawing of toughened poly(ethylene terephthalate). Part 2. Fracture behaviour

Mohanraj, J.; Chapleau, N.; Ajji, A.; Duckett, R. A.; Ward, I. M.

doi:10.1016/j.polymer.2004.10.090

Cited by 6 publications

(4 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the conditions for the validity of the EWF approach were not fulfilled, it was decided to employ the J ‐integral approach for the present study. This technique has been found to be successful for a wide variety of polymers and toughened polymers blends that exhibited plastic flow at the crack tip, either under quasistatic loading38–40 or impact loading conditions,41, 42 before fracture.…”

Section: Discussionmentioning

confidence: 99%

Fracture toughness of polymers in the ductile‐to‐brittle transition region: Statistical approach and lower bound determination

Cocco

Frontini

Ipiña

2005

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

A method available in literature was adapted and proposed for treating scatter and nonlinearity effects in fracture toughness of polymers in the ductile‐to‐brittle transition regime. The materials used were polypropylene homopolymer (PPH) and a polypropylene‐elastomeric polyolefin blend (PPH/POes 20 wt %), at room temperature and at 20‐mm/min test rate. Under such conditions, the fracture toughness presents a large scatter and a mean value can not be used as a design parameter because it leads to toughness overestimation. Then, there is a need to find a threshold of toughness, as a safe characteristic value for design. The toughness was evaluated by using the J‐integral approach. Large sets of specimens, 53 samples per each material, were tested with the purpose to reveal a reliable tendency in fracture behavior. As the toughness was considered nonuniform throughout the material, a weakest link model was assumed, and then results were analyzed statistically by means of a three‐parameter Weibull model (3P‐W). The PPH responded well to this 3P‐W model, whereas some deviations from the original model were observed in the PPH/POes blend. However, lower‐bound toughness values could be determined for both materials by censoring nonvalid data (Δa > 0.1b0). From an engineering point of view, the results are very encouraging, since this methodology allows to obtain a threshold of fracture toughness from a given population, that is suitable to characterize the material fracture toughness at a given temperature and strain rate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3674–3684, 2005

show abstract

Section: Discussionmentioning

confidence: 99%

Fracture toughness of polymers in the ductile‐to‐brittle transition region: Statistical approach and lower bound determination

Cocco

Frontini

Ipiña

2005

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…The increased interest of many research groups in the properties of PET/polyolefins blends is due to the neces-sity of preparing toughened materials from virgin PET [1][2][3][4][5][6] or developing new opportunities for postconsumer PET recycling [7][8][9][10]. In any case, the blending of these polymeric materials gives rise to multiphase systems, characterized by poor properties due to the high incompatibility.…”

Section: Introductionmentioning

confidence: 99%

Influence of compatibilizer precursor structure on the phase distribution of low density poly(ethylene) in a poly(ethylene terephthalate) matrix

Coltelli

Harrats

Aglietto

et al. 2008

Polymer Engineering & Sci

View full text Add to dashboard Cite

In attempt to enhance the compatibility of PET/LDPE blends by using a proper functionalized polymer as third component, diethyl maleate (DEM)-functionalized ultralow density poly(ethylene) (ULDPE-g-DEM) and styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS-g-DEM) were prepared by radical functionalization in the melt. Immiscible PET/LDPE blends having compositions of 70/30 and 80/20 by weight were then extruded in the presence of 1-10% by weight of ULDPE-g-DEM and SEBS-g-DEM as compatibilizer precursors and ZnO (0.3% by weight) as transesterification catalyst. In both cases, evidences about the occurring of compatibilization between the two immiscible phases, thanks to the studied reactive processes, were obtained. Moreover, the phase distribution and particle size of blends were deeply investigated. Completely different kinds of phase morphology were achieved, as ULDPE-g-DEM stabilized a dispersed phase morphology, whereas SEBS-g-DEM favored the development of a cocontinuous phase morphology. The observed differences are tentatively explained on the basis of reactivity and physical features of polymers.

show abstract

“…Most of the delivered energy was consumed during specimen bending rather than fracture. In contrast to the tensile properties, there was an optimum λ around 5, for which the impact strength was the highest [similar observations were noted for PP and poly(ethylene terephthalate)14–17 and in a review by Galeski18]. Dynamic mechanical measurements showed that rolling to a high strains (>6) produced not only a well‐developed orientation of the crystalline component but also a high orientation and transverse ordering of the amorphous phase, which led to the anisotropy of the material properties in the loading direction/constraint direction plane, perpendicular to the rolling direction.…”

Section: Introductionmentioning

confidence: 55%

Very high modulus high‐density polyethylene and high‐modulus polypropylene obtained by solid‐state roll drawing

Ajji

Dumoulin

2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

This article describes results obtained with a process developed for rolling and drawing simultaneously polymer profiles in the solid state. Solid-state roll drawing has the advantage of being continuous, which allows relatively high production rates and the generation of high deformation ratios with some degree of biaxial orientation. The roll-drawing process allows the extent of biaxial orientation to be controlled by the adjustment of the tension and compression loads applied to the polymers, in particular semicrystalline thermoplastics. Some experimental results obtained with a four-station roll-drawing apparatus are presented, particularly on high-density polyethylene (HDPE) and polypropylene. The effect of process parameters, such as the gap between the rolls and tension, are discussed.Aspects discussed also include relaxation; structure development in terms of orientation and crystallinity as a function of draw ratio (); as a function of process parameters; and finally, mechanical and thermal properties as a function of . Moduli as high as 25 GPa in the longitudinal direction and about 4 GPa in the transverse direction were obtained with successively rolled, initially thick, HDPE profiles.

show abstract

Roll-drawing and die-drawing of toughened poly(ethylene terephthalate). Part 2. Fracture behaviour

Cited by 6 publications

References 43 publications

Fracture toughness of polymers in the ductile‐to‐brittle transition region: Statistical approach and lower bound determination

Fracture toughness of polymers in the ductile‐to‐brittle transition region: Statistical approach and lower bound determination

Influence of compatibilizer precursor structure on the phase distribution of low density poly(ethylene) in a poly(ethylene terephthalate) matrix

Very high modulus high‐density polyethylene and high‐modulus polypropylene obtained by solid‐state roll drawing

Contact Info

Product

Resources

About