Thermal and morphological studies on isotactic polypropylene containing p-phenylen-bis-maleamic acid grafted groups

Cofrades, A.G; Areso, S.; García‐Martínez, Jesús María

doi:10.1016/s0014-3057(99)00296-7

Cited by 13 publications

(13 citation statements)

References 11 publications

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“…Our DSC measurements (the sample mass 16.4 mg, the heating rate 10 K/min) demonstrated the specific enthalpy of melting ⌬H m ϭ 77.6 J/g. This value of ⌬H m is quite comparable with the enthalpy of melting 78.1 J/g found by Collar et al, 62 and corresponds to the degree of crystallinity c ϭ 0.37 (when the value 209 J/g 63 is accepted as the enthalpy of fusion for a fully crystalline polypropylene).…”

Section: Methodssupporting

confidence: 86%

Model for the viscoelastic and viscoplastic responses of semicrystalline polymers

Drozdov

Christiansen

2003

J of Applied Polymer Sci

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Constitutive equations are derived for the time-dependent behavior of semicrystalline polymers at isothermal loading with small strains. A semicrystalline polymer at temperatures above the glass-transition point for its amorphous phase is thought of as a network of macromolecules bridged by junctions (physical crosslinks, entanglements, and crystalline lamellae) that can slide with respect to their reference positions in the bulk material under straining. The network is assumed to be highly inhomogeneous, and it is modeled as an ensemble of mesoregions (MRs) with various strengths of interchain interaction. Two types of MRs are distinguished: passive, where these interactions prevent detachment of strands from junctions; and active, where active strands separate from junctions and dangling strands merge with the network at random times as they are thermally agitated. The viscoelastic response of a semicrystalline polymer reflects reformation of strands in active MRs, whereas its viscoplastic behavior is associated with sliding of junctions. Stress-strain relations for uniaxial deformation are developed by using the laws of thermodynamics. Adjustable parameters in the constitutive equations are found by fitting experimental data for isotactic polypropylene in a tensile test with a constant strain rate and in tensile relaxation tests at various strains. Fair agreement is demonstrated between the observations and the results of numerical simulation. It is revealed that the viscoplastic flow of junctions strongly affects the rearrangement process in active MRs, whose rate reaches a threshold value in the vicinity of the apparent yield point.

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Section: Methodssupporting

confidence: 86%

Model for the viscoelastic and viscoplastic responses of semicrystalline polymers

Drozdov

Christiansen

2003

J of Applied Polymer Sci

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“…[22] The segregation of the grafted material and its exclusion from crystalline zones of the sample [23] leads to improved functionality at the polymer -mineral interface. The improvement in the modulus of iPP -mica composites with a succinyl-flourescein grafted atactic polypropylene (aPP) agent has been shown to be a function of the grafting level in the interfacial agent.…”

Section: Polypropylene-mineral Compositesmentioning

confidence: 99%

The Study of Heterogeneous Polymer Systems by Synchrotron Infrared Microscopy

Ellis

Marco

Gómez

et al. 2004

Journal of Macromolecular Science, Part B

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“…26 In the case of polypropylene, functionalization generally leads to an increase in the crystallinity, which is attributed to chain scission and increased degree of order. 7,27,28 …”

Section: Resultsmentioning

confidence: 99%

Grafting of tetrahydrophthalic and maleic anhydride onto polyolefins in solution

Campos

Fantini

Petri

2004

J. Braz. Chem. Soc.

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Polietileno de baixa densidade (LLDPE) com comonômeros 1-buteno e 1-octeno foram funcionalizados com anidrido tetrahidroftálico (THA) e anidrido maléico (MA) em solução na presença de peróxido de benzoíla (BPO), de acordo com planejamentos fatoriais. As variáveis testadas foram concentração de anidrido, concentração de peróxido, tempo de reação e tipo de comonômero. As formulações foram analisadas por espectroscopia vibracional no infravermelho FTIR. Na funcionalização com THA o efeito principal tempo de reação foi significativo, assim como, a interação deste com a concentração de THA, enquanto que no caso do MA as concentrações de BPO e MA foram significativas. Poliolefinas modificadas com teores semelhantes de THA e MA foram analisadas por calorimetria exploratória diferencial (DSC) e por difração de raios X (XRD). Amostras modificadas com THA e MA apresentaram redução na temperatura de fusão de 4,3 °C e 1,4 °C, respectivamente, com relação ao polímero original. Alterações devido à funcionalização também foram evidenciadas por forte redução nas áreas dos picos de difração relativos aos planos cristalinos (110) e (200), corroborando com os dados de calorimetria exploratória diferencial (DSC).Tetrahydrophthalic (THA) and maleic (MA) anhydrides were grafted onto linear low density polyethylene with comonomer 1-butene and 1-octene (LLDPE) in solution in the presence of benzoyl peroxide (BPO) following experimental designs, where anhydride and BPO concentrations, type of comonomer and reaction time were varied. The formulations were analyzed by Fourier transform infrared spectroscopy (FTIR). In the case of THA modified polyolefins, the time of reaction and the interaction between time of reaction and THA concentration influenced the process, whereas the MA and BPO concentrations influenced the grafting of MA onto polyolefins. THA and MA modified polyolefin samples with similar grafting contents were analized by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). THA and MA functionalized polyolefins presented reduction in the melting temperature of 4.3 °C and 1.4 °C, respectively, comparing with the original polymer. These effects corroborate with the strong reduction in the areas of the diffraction peaks (110) and (200) after the grafting process.

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Thermal and morphological studies on isotactic polypropylene containing p-phenylen-bis-maleamic acid grafted groups

Cited by 13 publications

References 11 publications

Model for the viscoelastic and viscoplastic responses of semicrystalline polymers

Model for the viscoelastic and viscoplastic responses of semicrystalline polymers

The Study of Heterogeneous Polymer Systems by Synchrotron Infrared Microscopy

Grafting of tetrahydrophthalic and maleic anhydride onto polyolefins in solution

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