Monitoring the chemical crosslinking of propylene polymers through rheology

Romani, Francesco; Corrieri, R.; Braga, Vagner; Ciardelli, Francesco

doi:10.1016/s0032-3861(01)00679-6

Cited by 118 publications

(99 citation statements)

References 15 publications

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“…Even in that case the magnitude of the peak decreased with an increase in the filler concentration, whereas tanδ values corresponding to the peak increased with the filler concentration. Romani et al [56] attributed the existence of a tanδ peak to a critical relaxation behavior involved in a high-order structure within the polymer matrix, related to the existence of interparticle networks. Therefore, it is likely that similar considerations could be extended to LLDPE filled with aggregated physically interacting nanoparticles.…”

Section: Rheological Measurementsmentioning

confidence: 99%

Linear low-density polyethylene/silica micro- and nanocomposites: dynamic rheological measurements and modelling

Dorigato¹,

Pegoretti²,

Penati³

2010

Express Polym. Lett.

106

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Abstract. Linear low-density polyethylene (LLDPE) based composites were prepared by melt compounding with 1, 2, 3 and 4 vol% of various kinds of amorphous silicon dioxide (SiO2) micro-and nanoparticles. Dynamic rheological tests in parallel plate configuration were conducted in order to detect the role of the filler morphology on the rheological behaviour of the resulting micro-and nanocomposites. A strong dependence of the rheological parameters from the filler surface area was highlighted, with a remarkable enhancement of the storage shear modulus (G′) and of the viscosity (η) in fumed silica nanocomposites and in precipitated silica microcomposites, while glass microbeads only marginally affected the rheological properties of the LLDPE matrix. This result was explained considering the formation of a network structure arising from particle-particle interactions due to hydrogen bonding between silanol groups. A detailed analysis of the solid like behaviour for the filled samples at low frequencies was conducted by fitting viscosity data with a new model, based on a modification of the original De Kee-Turcotte expression performed in order to reach a better modelling of the high-frequency region.

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Section: Rheological Measurementsmentioning

confidence: 99%

Linear low-density polyethylene/silica micro- and nanocomposites: dynamic rheological measurements and modelling

Dorigato¹,

Pegoretti²,

Penati³

2010

Express Polym. Lett.

106

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“…These are important characteristics for the preparation of fibers and materials capable of being processed by blow molding. 1 In addition, crosslinked polyethylene (PE) is widely used in the wire and cable coating, and in the preparation of heat shrinkable materials. 2,3 PE is an easily crosslinking polymer, which is prepared by means of an organic peroxide capable of creating radicals by a decomposition reaction, or by irradiation with different doses of electron beam.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, in the last year, new methods to achieve the crosslinking of the iPP have been developed. 1,6 The present study deals with an innovative method that allows the preparation of reversibly crosslinked iPP. 7 This method, with slight variations, can be used to obtain crosslinked blends of PP and low or high density PE, copolymers of iPP or their blends with elastomers.…”

Section: Introductionmentioning

confidence: 99%

Structure modification of isotactic polypropylene through chemical crosslinking: Toughening mechanism

Bouhelal¹,

Cagiao²,

Benachour³

et al. 2006

J of Applied Polymer Sci

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Reversibly crosslinked isotactic polypropylene (iPP) was prepared in the presence of dicumyl peroxide. The effects of the peroxide oxy-radicals in the melt were investigated in relation to the modification of the polymer. The dynamic rheology analysis of the crosslinking process was carried out by using a plastograph. The crosslinking reaction was evaluated by the Monsanto method. The resulting structure of the modified samples was studied by means of differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), microhardness, and mechanical properties. The degree of crystallinity of the modified iPP, derived from DSC and WAXS, remains almost unchanged, i.e., the crystalline structure is unaffected, though the lamellar thickness slightly decreases. The impact strength of the crosslinked iPP is greatly improved with reference to that of the unmodified material. A transition from brittle to ductile behavior appears in the modified iPP for all the crosslinking agents studied.

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“…Such a result has been already reported by Braun et al on an iPP + peroxide system, in the absence of EPDM [17] . To effectively crosslink the iPP in the presence of a peroxide, it is necessary to use a coagent, i.e., a furan or bismaleimide based one [18] . Moreover, a new method, which allows the reversible crosslinking of the iPP, has been recently developed [19] .…”

Section: Binary Blendsmentioning

confidence: 99%

Study of rheological and mechanical properties of ternary blends of iPP/LDPE/EPDM

Bouhelal¹,

Cagiao²,

Lorenzo³

et al. 2012

Journal of Polymer Engineering

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Compatible blends of isotactic polypropylene (iPP)/lowdensity polyethylene (LDPE)/ethylene-propylene-diene monomer (EPDM) were prepared by reactive blending in the presence of dicumyl peroxide (DCP). The blends were characterized using different techniques: dynamical rheological analysis (DRA), differential scanning calorimetry (DSC), optical microscopy (OM) and scanning electron microscopy (SEM), dynamical mechanical thermal analysis (DMTA), viscosity and impact strength, to evaluate their properties. Results revealed that the presence of the peroxide in LDPE/ EPDM blends gives rise to crosslinking reactions, as is the case in iPP/LDPE/EPDM blends. However, in the latter case, scission reactions of the iPP component also take place. As a consequence of the whole process, morphological changes arise mainly in the amorphous regions, without affecting the degree of crystallinity of the components. The mechanical properties of the blends are consequently improved, due to the crosslinked network thus formed in the blends.

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Monitoring the chemical crosslinking of propylene polymers through rheology

Cited by 118 publications

References 15 publications

Linear low-density polyethylene/silica micro- and nanocomposites: dynamic rheological measurements and modelling

Linear low-density polyethylene/silica micro- and nanocomposites: dynamic rheological measurements and modelling

Structure modification of isotactic polypropylene through chemical crosslinking: Toughening mechanism

Study of rheological and mechanical properties of ternary blends of iPP/LDPE/EPDM

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