Toughening of polypropylene by different elastomeric systems

Yokoyama, Yoshihiko; Riccò, T.

doi:10.1016/s0032-3861(97)10358-5

Cited by 114 publications

(71 citation statements)

References 19 publications

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“…25,26 In particular, a NMR imaging study of stress-induced material response carried out by Adriaensens and coworkers 25 on rubber modified nylon has shown that the toughness of the material is strongly related to the load bearing capacity of the cavitated rubber particles in dilatational bands. In fact, after cavitation, the biaxial stretching of the rubbery layer attached to the cavity walls 26 can stabilize the growing dilatational band by absorbing elastic energy, delaying strain localization and premature failure. Under impact conditions, thermal failure may also occur in the ligaments between particles.…”

Section: Discussionmentioning

confidence: 99%

“…They found that the blend in which the rubbery phase had superior elastic properties, due to physical and topological constraints, also showed enhanced toughness and a more extended plastic zone ahead of the crack tip. Also, Riccò and coworkers 26 reported that, in rubber toughened PP, ethylenebutene rubber (EBR) was more effective than EPR in enhancing the fracture toughness of PP blends, despite a lower tendency to cavitate. Improvement of the fracture resistance was also achieved by the same authors by increasing the molecular mass of the elastomers.…”

Section: Discussionmentioning

confidence: 99%

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Deformation, yield and fracture of elastomer‐modified polypropylene

Zebarjad

Bagheri

Reihani

et al. 2003

J of Applied Polymer Sci

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ABSTRACT:In recent decades, great attention has been devoted to the toughening of isotactic poly(propylene) (PP) with elastomers such as ethylene-propylene rubber (EPR). The most important reasons for this interest are the moderate cost and favorable properties of PP. This article is focused on the role of EPR in the deformation and fracture mechanism of PP/EPR blends with different volume fractions of elastomer phase. Differential scanning calorimetry (DSC), tensile tests, and microscopy techniques were used in this study. The fracture mechanism of isotactic PP toughened by EPR (PP/EPR) has also been studied by three point bending (3-PB) and four point bending (4-PB) tests. Rubber particle cavitation appears to be the main mechanism of microvoid formation, although some matrix/particle debonding was observed. The investigation of the toughening mechanism shows that a wide damage zone spreads in front of the pre-crack. Optical microscopy (OM) illustrates that, in pure PP, crazing is the only fracture mechanism, and no evidence of shear yielding is found, while in PP blends craze-like features associated with shear yielding are observed, which have been identified as high shear localized dilatational bands. This type of deformation pattern supports a model previously proposed by Lazzeri 1 to explain the interparticle distance effect on the basis of the stabilization effect on dilatational band propagation exerted by stretched rubber particles.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Deformation, yield and fracture of elastomer‐modified polypropylene

Zebarjad

Bagheri

Reihani

et al. 2003

J of Applied Polymer Sci

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“…The easier the shear yielding of the matrix, the better impact toughness of the blends has. 38,39 The shear yielding of the matrix is dependent on the matrix properties, for example, the spherulites size of the matrix. The shear yielding of matrix becomes more difficult with the increase of the spherulites size possibly due to the stress propagation becomes more difficult.…”

Section: Synergistic Toughening Effect and Mechanismsmentioning

confidence: 99%

Synergistic toughening effects of nucleating agent and ethylene–octene copolymer on polypropylene

Bai

Wang

Song

et al. 2008

J of Applied Polymer Sci

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ABSTRACT:The synergistic toughening effect of nucleating agent (NA) and ethylene-octene copolymer (POE) on polypropylene was studied in the present work. Two different nucleating agents, such as a-form nucleating agent 1,3 : 2,4-bis (3,4-dimethylbenzylidene) sorbitol (DMDBS, Millad 3988) and b-form nucleating agent aryl amides compounds (TMB-5), were selected to blend with PP or PP/POE blends, respectively. The results show that PP containing 0.5-0.25 wt % DMDBS or 0.5-0.25 wt % TMB-5 has relatively low impact strength. For PP/POE blends, although the impact strength increases gradually with the increasing of POE content, high content of POE is needed to obtain the available PP toughness. However, once nucleating agent and POE are simultaneously added into PP, PP/POE/NA blends show great improvement of toughness even at low POE content. Furthermore, the synergistic toughening effect of POE/TMB-5 is more apparent than that of POE/DMDBS. SEM results show that whether DMDBS or TMB-5 has no apparent effect on the morphologies of POE in the PP/POE/NA blends. Further investigations using DSC and POM indicate that both DMDBS and TMB-5 induce the apparent enhancement of the crystallization temperature of PP and the sharp decrease of spherulites size of PP in the PP/POE/NA blends. The possible synergistic toughening mechanism is discussed in the work.

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“…It was, therefore, selected for this study as an appropriate major component polymer. Some degree of success has been achieved in modification of PP using rubber additives [16][17][18][19][20][21], but noticeable reductions in stiffness and scratch/mar resistance can occur in the resulting blends [22]. Blends of PP and low density polyethylene (LDPE) may give a better balance between toughness improvements and stiffness reductions.…”

Section: Introductionmentioning

confidence: 99%