Influence of structure on the properties of polypropylene copolymers and terpolymers

Caveda, Susana; Pérez, Ernesto; Blázquez‐Blázquez, Enrique; Peña, Begoña; Grieken, Rafael van; Suárez, Inmaculada; Benavente, Rosario

doi:10.1016/j.polymertesting.2017.06.008

Cited by 17 publications

(12 citation statements)

References 55 publications

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“…Moreover, the γ modification is also specially boosted in iPP synthesized by metallocene catalysts due to the presence of errors homogeneously distributed among polymeric chains [ 37 ]. The γ form in polypropylene-based materials is more easily developed when crystallization is performed at relatively low rates [ 3 , 31 , 32 ]. The standard processing used in industry for the manufacture of pipes implies that the outer side is cooled faster than the inner parts, since the heat dissipation is slower in the inner parts than in the outer parts.…”

Section: Resultsmentioning

confidence: 99%

“…PP-R piping products are considered for continuous operation at a temperature of 82 °C, with pressure ratings dependent on their wall type. Ethylene or 1-butene are the common comonomers in PP-R and their incorporation leads to a decrease in crystallinity, rigidity, melting and glass transition temperatures in the resultant materials, compared with those properties exhibited by a PP homopolymer [ 1 , 2 , 3 , 4 ]. These characteristics provide a high elasticity and a great impact resistance to the PP-R pipes, which are very advantageous for their final use.…”

Section: Introductionmentioning

confidence: 99%

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An Effective Package of Antioxidants for Avoiding Premature Failure in Polypropylene Random Copolymer Plastic Pipes under Hydrostatic Pressure and High Temperature

Blázquez‐Blázquez

Lahoz²,

Pérez

et al. 2021

Polymers

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Pipes of polypropylene random (PP-R) copolymers are the best choice for hot- and cold-water networks. Validation of a severe test, accomplishing the ISO 1167 standard, is mandatory to assess their service lifetime expectancy. This work evaluates the behavior shown by three commercial pipes, either the original ones (new pipes) or after being subjected to a hydrostatic pressure test at elevated temperature (aged pipes). Several features with relevance for the final performance have been examined: crystalline characteristics, phase transitions in crystalline regions, effect of high temperature and pressure on these transitions, and oxidation induction time. Moreover, the presence of inorganic fillers, and the content of different antioxidants together with their depletion, have also been analyzed. Films from the new pipes were also prepared for replication of the different environments in order to achieve a better and complete understanding of the phase transitions in the crystalline regions and of the consumption of antioxidants. Distinct environments surrounded the inner and outer parts of the pipes exposed to the failure aging test at 110 °C: hot water and warm dry air, respectively. These features play a key role in the loss of additives and in the subsequent initiation of degradation. Even if the crystalline characteristics are appropriate in the polymeric matrix, the success of a pipe lies in the homogeneous dispersion of components for avoiding damage at interfacial properties, and in a correct package of antioxidants used in its formulation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Effective Package of Antioxidants for Avoiding Premature Failure in Polypropylene Random Copolymer Plastic Pipes under Hydrostatic Pressure and High Temperature

Blázquez‐Blázquez

Lahoz²,

Pérez

et al. 2021

Polymers

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“…The formation of b crystals in copolymers and terpolymers of iPP, achieved by the addition of a b nucleant, was found to be highly dependent on comonomer type and crystallization conditions due to the competition with the g-form. 32 The mechanical behavior exhibited by these specimens turns out to be very interesting because of the considerable changes that incorporation of b nucleating agents provokes 12 in the crystalline structure. In this work, the viscoelastic behavior has been analyzed.…”

Section: Resultsmentioning

confidence: 99%

“…The formation of β crystals in copolymers and terpolymers of iPP, achieved by the addition of a β nucleant, was found to be highly dependent on comonomer type and crystallization conditions due to the competition with the γ -form. 32…”

Section: Resultsmentioning

confidence: 99%

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

Belkouicem¹,

Benarab²,

Krache³

et al. 2018

Journal of Elastomers & Plastics

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The influence of two thermal treatments on the structure, morphology, and ultimate properties exhibited by isotactic polypropylene (iPP), synthesized by conventional Ziegler–Natta iPP (Z-iPP) or metallocene iPP (m-iPP) catalysts, has been investigated in the present work. Novelty of this research consisted in the incorporation of a β nucleating agent in two different contents to the m-iPP. Results attained are compared with those found in the Z-iPP and important differences are observed. Differential scanning calorimetry and X-ray diffraction experiments revealed that coexistence of different crystalline lattices took place depending on the type of iPP: β and α forms were found in the β nucleated Z-iPP specimens, whereas α, β, and γ polymorphs could be developed in the m-iPP with nucleating agent. On the other hand, the iPP glass transition temperature ( Tg) did not exhibit a significant change because of the addition of β nucleant, as deduced from Dynamic Mechanical Thermal Analysis (DMTA) analysis. Moreover, the size and shape of the iPP spherulites was totally changed by the presence of the β agent. This nucleant promoted the formation of smaller spherulites in a greater amount, as demonstrated by optical microscopy. Concerning the mechanical parameters, microhardness, MH, and Young modulus, E, values were in the fast crystallized samples lower than those presented by their slowly cooled counterparts. A good balance in properties was seen for the slowly crystallized m-iPP that incorporated a 5 wt% content in β nucleating agent, this fact being ascribed to the coexistence of the three α, β, and γ polymorphs.

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“…Among PP polymers, there is a special classed named polypropylene random copolymer (PPR), which according to standard ASTM F2389, is based on propylene and at least one comonomer, with propylene being above 50% of the composition. The most usual comonomers are ethylene or 1-butene, and their presence involves certain decreases of the glass transition and melting temperatures and of the crystallinity and rigidity in relation to the properties exhibited by PP homopolymers [ 28 , 29 , 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Composites of a Polypropylene Random Copolymer and Date Stone Flour: Crystalline Details and Mechanical Response

et al. 2021

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Several composites were prepared based on a polypropylene random copolymer (PPR) and different amounts of date stone flour (DSF). This cellulosic fiber was silanized beforehand in order to reduce its hydrophilicity and improve the interfacial adhesion with the polymer. Other composites were also obtained, including a sorbitol derivative as an effective nucleant. Films made from these composites were prepared using two different thermal treatments, involving slow crystallization and rapid cooling from the melt. Scanning electron microscopy was used to evaluate the morphological features and the DSF particle dispersion within the PPR matrix. X-ray diffraction experiments and differential scanning calorimetry tests were employed to assess the crystalline characteristics and for the phase transitions, paying especial attention to the effects of the DSF and nucleating agent on PPR crystallization. An important nucleation ability was found for DSF, and evidently for the sorbitol derivative. The peak crystallization temperature upon cooling was considerably increased by the incorporation of either the nucleant or DSF. Additionally, a much higher proportion of orthorhombic crystals developed in relation to the monoclinic ones. Moreover, the mechanical responses were estimated from the microhardness experiments and significant improvements were found with increasing DSF contents. All of these findings indicate that the use of silanized DSF is a fairly good approach for the preparation of polymeric eco-composites, taking advantage of the widespread availability of this lignocellulosic material, which is otherwise wasted.

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Influence of structure on the properties of polypropylene copolymers and terpolymers

Cited by 17 publications

References 55 publications

An Effective Package of Antioxidants for Avoiding Premature Failure in Polypropylene Random Copolymer Plastic Pipes under Hydrostatic Pressure and High Temperature

An Effective Package of Antioxidants for Avoiding Premature Failure in Polypropylene Random Copolymer Plastic Pipes under Hydrostatic Pressure and High Temperature

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

Composites of a Polypropylene Random Copolymer and Date Stone Flour: Crystalline Details and Mechanical Response

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