Synthesis of Long-Chain Branched Propylene Polymers via Macromonomer Incorporation

Weng, Weiqing; Markel, Eric J.; Dekmezian, Armenag H.

doi:10.1002/1521-3927(20011201)22:18<1488::aid-marc1488>3.0.co;2-i

Cited by 62 publications

(72 citation statements)

References 5 publications

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“…Therefore, the choice of one polymeric material type or another (copolymers or blends) has to be taken as a function of the best compromise between rigidity and toughness necessary to accomplish the final requirements for a specific application. The metallocene block copolymers with soft and hard domains10–13 synthesized with rubbery polyolefin macromonomers might also be a very interesting approach.…”

Section: Resultsmentioning

confidence: 99%

“…), with only the structure of the catalyst being changed 8, 9. Moreover, these metallocene catalysts allow the incorporation of rubbery polyolefinic macromonomers, such as atactic polypropene10 and poly(ethylene‐ co ‐propylene),11–13 into macromolecules, making feasible the coexistence of hard and soft segments within the chains. These novel copolymers constitute a very interesting approach to stiffness/impact resistance optimization.…”

Section: Introductionmentioning

confidence: 99%

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Metallocene copolymers of propene and 1‐hexene: The influence of the comonomer content and thermal history on the structure and mechanical properties

López-Majada

Palza

Guevara

et al. 2006

J Polym Sci B Polym Phys

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The relationships between the structure and properties have been established for copolymers of propylene and 1‐hexene synthesized with an isotactic metallocene catalyst system. The most important factor affecting the structure and properties of these copolymers is the comonomer content. The thermal treatment, that is, the rate of cooling from the melt, is also important. These factors affect the thermal properties, the degree of crystallinity, and therefore the structural parameters and the viscoelastic behavior. A slow cooling from the melt favors the formation of the γ phase instead of the α modification. Regarding the viscoelastic behavior, the β relaxation, associated with the glass‐transition temperature, is shifted to lower temperatures and its intensity is increased as the 1‐hexene content raises. The microhardness values are correlated with those of the storage modulus deduced from dynamic mechanical thermal analysis curves, and good linear relations have been obtained between these parameters. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1253–1267, 2006

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Metallocene copolymers of propene and 1‐hexene: The influence of the comonomer content and thermal history on the structure and mechanical properties

López-Majada

Palza

Guevara

et al. 2006

J Polym Sci B Polym Phys

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“…It was quite surprising that the fibers of molecularly oriented polyester having no specific interchain interaction could be so easily formed because the widely studied oriented polyester fiber was derived from a high‐speed drawing of high‐molecular‐weight polymer melts. The present orientation may be due to the specific structure of the four‐way cranked branching point, as shown in Figure 6A, suggesting a hyperbranch architecture that effectively increases the extensional viscosity 28. These arms can behave as a rigid‐rod bundle of polymeric chains, thus enabling their LC properties to result in successful spinning of the fibers with a macroscopic molecule orientation.…”

Section: Copolymers From Multifunctional Biomonomersmentioning

confidence: 95%

High‐performance functional ecopolymers based on flora and fauna

Kaneko¹

2007

The Chemical Record

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Liquid crystalline (LC) polymers of rigid monomers based on flora and fauna were prepared by in-bulk polymerization. Para-coumaric (p-coumaric) acid [4-hydroxycinnamic acid (4HCA)] and its derivatives were selected as phytomonomers and bile acids were selected as biomonomers. The 4HCA homopolymer showed a thermotropic LC phase only in a state of low molecular weight. The copolymers of 4HCA with bile acids such as lithocholic acid (LCA) and cholic acid (CA) showed excellent cell compatibilities but low molecular weights. However, P(4HCA-co-CA)s allowed LC spinning to create molecularly oriented biofibers, presumably due to the chain entanglement that occurs during in-bulk chain propagation into hyperbranching architecture. P[4HCA-co-3,4-dihydroxycinnamic acid (DHCA)]s showed high molecular weight, high mechanical strength, high Young's modulus, and high softening temperature, which may be achieved through the entanglement by in-bulk formation of hyperbranching, rigid structures. P(4HCA-co-DHCA)s showed a smooth hydrolysis, in-soil degradation, and photo-tunable hydrolysis. Thus, P(4HCA-co-DHCA)s might be applied as an environmentally degradable plastic with extremely high performance.

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“…Another route to introduce LCB is to use macromononers. 10 While there has been extensive work and research done on the synthesis of branched polypropylene and polyethylene, there has been a limited amount of work done in the area of engineering resins. [11][12][13][14][15] Fluoropolymers, an important class of engineering resins, find applications in three main areas: melt processing such as extrusion and injection molding, architectural coatings, and porous membranes produced by solvent casting.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Randomly Branched Poly(vinylidene fluoride)

et al. 2008

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Poly(vinylidene fluoride) (PVDF) experimental samples containing sparsely distributed chain branching were compared to commercial reference samples. The results showed a lower onset of shear thinning for the branched samples over the reference counterparts. The storage modulus of the branched samples at low frequency shows a significant increase for the low-molecular weight sample while the higher-molecular weight sample showed a moderate increase suggesting a strong contribution of chain branching. The branched PVDF samples exhibited a lower radius of gyration (R G ) and intrinsic viscosity than the commercial samples over the entire molecular weight range. NMR revealed the presence of tertiary carbons, suggesting that the branches are covalently bonded and not of a physical nature. Extensional viscosity data showed that the branched samples display a significant degree of strain hardening while the reference samples exhibit a small degree of strain hardening.

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Synthesis of Long-Chain Branched Propylene Polymers via Macromonomer Incorporation

Cited by 62 publications

References 5 publications

Metallocene copolymers of propene and 1‐hexene: The influence of the comonomer content and thermal history on the structure and mechanical properties

Metallocene copolymers of propene and 1‐hexene: The influence of the comonomer content and thermal history on the structure and mechanical properties

High‐performance functional ecopolymers based on flora and fauna

Characterization of Randomly Branched Poly(vinylidene fluoride)

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