Crystalline modifications of lineartrans-quinacridone pigments

Filho, Dibai; Oliveira, Clara Marize F.

doi:10.1007/bf01105280

Cited by 30 publications

(22 citation statements)

References 6 publications

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“…The quinacridone pigment is formed from five‐ring polycyclic organic molecules of dimensions 1.406 × 0.52 nm 26. The molecule is planar with no significant departure of the carbonyl groups from a molecular plane defined by all nonhydrogen atoms.…”

Section: Discussionmentioning

confidence: 99%

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Nucleating activity of the quinacridone and phthalocyanine pigments in polypropylene crystallization

Broda¹

2003

J of Applied Polymer Sci

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ABSTRACT:The nucleating ability of two organic pigments, quinacridone and phthalocyanine, in nonisothermal polypropylene (PP) crystallization was investigated. The investigations were carried out using DSC and polarizing microscopy. The efficiency of pigments in the nucleation process was determined in a simple test comparing the crystallization temperature of the PP-containing pigments with respect to the pure polymer. Both pigments revealed good nucleating activity. In the presence of pigments the increment of the crystallization temperature and the increase of nucleation rate were observed. The nucleating efficiency of pigments was confirmed in investigations of the obtained structure. The nucleating activity of pigments was explained by their features fulfilling several requirements for good nucleating agents.

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Section: Discussionmentioning

confidence: 99%

“…The quinacridone can exist in several crystal modifications 26, 28. Most synthetic methods lead to the formation of an unstable α‐form.…”

Section: Discussionmentioning

confidence: 99%

Nucleating activity of the quinacridone and phthalocyanine pigments in polypropylene crystallization

Broda¹

2003

J of Applied Polymer Sci

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“…Two different commercial pigments, Hostaperm E3B and Hostaperm EO 1, kindly supplied by Hoechst AG, were used as nucleating agents. A linear transquinacridone dye ( y-modification) (PV E3B) consisting of a planar molecule of five fused rings of dimensions 1.406 nm X 0.52 nm (40,50) was used as p-nucleating agent. I t is an infusible substance, and sublimation was observed near 425°C.…”

Section: Nucleating Agentsmentioning

confidence: 99%

Trans‐ and Dimethyl quinacridone nucleation of isotactic polypropylene

Sterzyński¹,

Calo²,

Lambla³

et al. 1997

Polymer Engineering & Sci

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Isotaclic polypropylene (iPP) was nucleated specifically for structural and mechanical studies, especially of impact resistance. Nucleation was accomplished by two red pigments: a linear trans‐quinacridone dye (as β‐phase nucleator) and a dimethyl quinacridone resulting in the formalion of a pure α‐phase structure. This procedure allowed the comparison of both the crystal structure and the morphology of the polymer. For the β‐nucleated iPP, by means of the WAXS measurements in the transmission mode, a maximum of the k‐value (fraction of β‐phase) was found for a concentration of 5 × 10−5 wt% of the trans‐quinacridone. By means of polarized light microscopy (PLM), the mold temperature and pigment concentration dependent spherulites distribution on the cross section of the samples was observed. DSC permitted confirmation of the WAXS measurements, giving a characteristic double melting peak for the β polypropylene. By isothermal WAXS measurements the temperature of 135°C as the upper limit of the β phase was detected. For both nucleating agents (linear trans‐quinacridone and dimethyl quinacridone) the dependence of the mechanical properties (modulus of elasticity and brittleness by impact resistance) on the pigment concentration was observed. For the β‐phase iPP the highest ductility by impact testing corresponds to the highest values of the k parameter. The explanation is based on the SEM observations, which permitted the detection of spherulites with cross‐hatched lamellae (for the α‐spherulites) and with simple radial growth lamellae for the β‐spherulites.

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“…Quinacridone pigment crystallizes, forming several crystal modifications with very high thermal stability 34–36. The benzene rings of the γ modification form a structural periodicity on the surface of the quinacridone crystal, which insures nearly perfect matching with a helix distance of the poly(propylene) chain 37, 38.…”

Section: Introductionmentioning

confidence: 99%

Influence of processing on structure of β‐nucleated poly(propylene) fibers

Broda

2003

J of Applied Polymer Sci

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Fibers colored with quinacridone pigment spun at low take-up velocities were obtained. The spun fibers, with a very high ␤-form content, were drawn at room temperature and at a temperature of 120°C at different draw ratios. They were then heat stabilized at different temperatures, ranging from 140 to 150°C for different time intervals. As a result of drawing, the transition from ␤ to mesophase, as well as that from ␤ to ␣, was observed. The ␤ to mesophase transition results from cold drawing at room temperature, while the ␤ to ␣ transition results from drawing at 120°C. In both cases, the significant decrease of ␤-form content occurs at the low draw ratio of 2. At higher draw ratios, the ␤-form content gradually decreases, and at a draw ratio of 7 the ␤-form disappears altogether. As a result of heat stabilization, the ␤ to ␣ transformation was observed. The first change of the ␤-form content was noticed at 140°C. For fibers stabilized at temperatures above 140°C, the decrease of the ␤-form content is more significant and increases with the increase of the stabilization temperature. At 150°C, a rapid drop of the ␤-form content occurs after only 3 min, and after a few more minutes the ␤-form disappears.

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Crystalline modifications of lineartrans-quinacridone pigments

Cited by 30 publications

References 6 publications

Nucleating activity of the quinacridone and phthalocyanine pigments in polypropylene crystallization

Nucleating activity of the quinacridone and phthalocyanine pigments in polypropylene crystallization

Trans‐ and Dimethyl quinacridone nucleation of isotactic polypropylene

Influence of processing on structure of β‐nucleated poly(propylene) fibers

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