Controlling of higher order structure of polypropylene with a nucleating additive.

Ikeda, Kiyoshi

doi:10.1295/koron.46.45

Cited by 4 publications

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“…The nucleating activity of a foreign grain should be proportional to their size. Because the bigger particle has a greater surface area may offer a greater site for nucleation than a small one [25][26][27] .…”

Section: Crystalline Morphology On Glass Fibrementioning

confidence: 99%

Rf Plasma Polymerisation for the Improvement of Interfacial Adhesion between Glass Fibres and Polybutene-1

Chou

Shih

Chen

2001

Polymers and Polymer Composites

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Radio frequency (RF) plasma polymerisation is used to treat glass fibres to improve the interfacial adhesion between polybutene-1 and glass fibre. After the glass fibres were treated with coupling agent, four different monomers were polymerised onto the surface by plasma. The plasma polymers changed the surface morphology and surface free energy of the fibre surfaces. The experimental results indicate that a grain-like surface induces a transcrystalline layer to form onto the fibre surface to improve the polybutene-1/glass fibre interfacial shear strength relative to glass fibres treated with coupling agent only. The glass fibre treated with coupling agent, then treated with acrylonitrile and styrene increased the interfacial adhesion strength by 71% and 78%respectively. Glass fibre surfaces treated with grain-like organosilicon, then plasma polymerised tetramethylsilane (ppTMS) and hexamethyldisiloxane (ppHMDSO), allow a transcrystalline layer to form and this increases the interfacial shear strength by 187% and 180% respectively, achieving 100% and 97% higher strength than when treated with coupling agent only.

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Section: Crystalline Morphology On Glass Fibrementioning

confidence: 99%

Rf Plasma Polymerisation for the Improvement of Interfacial Adhesion between Glass Fibres and Polybutene-1

Chou

Shih

Chen

2001

Polymers and Polymer Composites

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Crystal orientation in injection molding of talc‐filled polypropylene

Fujiyama

Wakino

1991

J of Applied Polymer Sci

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SYNOPSISThe crystal orientation in injection molding of talc-filled polypropylene has been studied by means of polarizing microscopy and X-ray diffraction measurements. The plate planes of talc particles are aligned parallel to the surface of injection molding. The c-and a*-axes of polypropylene crystals are bimodally oriented to the flow direction, and the b-axes are oriented to the thickness direction. Namely, the crystals in the injection molding of talcfilled polypropylene show a kind of uniplanar-axial orientation according to the classification of Heffelfinger and Burton. The degree of the bimodal orientation of c-and a*-axes decreases toward the interior of the injection molding. The b-axis orientation is strong throughout the thickness direction, although it is a little weaker at the surface skin and central regions. This peculiar crystal orientation originates from the flaky shape and crystallization nucleation ability of talc particles. In a mold cavity, talc particles are aligned parallel to the cavity wall by the action of flow, and crystallization progresses, with the (040) plane of polypropylene crystal piling on the plate planes of talc particles and the b-axis, which is the growth direction of polypropylene crystal, being aligned to the thickness and cooling direction of injection molding. The crystal orientation in injection molding of unfilled polypropylene is basically similar to that of talc-filled polypropylene, although the b-axis orientation to the thickness direction is much weaker. INTRODUCTIONIn injection molding of plastics, since a molten resin flows into a cold mold cavity at high speed, where it is solidified, orientation of molecular chains occurs, significantly affecting product properties such as mechanical and optical properties. In the case of injection molding of semicrystalline polymers, since the molecular chains are crystallized under a stress, orientation of crystallites occurs. Several studies have so far been done on the orientation state of crystals in injection-molded semicrystalline polymers.l-12Clark2 found from X-ray diffraction measurement that the skin layer in injection-molded polypropylene has a mixed c-axis and a*-axis orientation, which he called bimodal; he explained its formation * To whom correspondence should be addressed.Journal of Applied Polymer Science, Vol. 42,9-20 (1991) by assuming that the c -axis-oriented component was formed first, and that the a*-axis component was formed by epitaxial overgrowth on the c -axis-oriented substrate. Kantz et a12 made X-ray diffraction measurements on the skin layer in injection-molded polypropylene from various directions and found that crystallites are biaxially oriented to MD and that the tensile yield strength and mold shrinkage in MD were higher as the skin layer was thicker.Mencik and Fitchmun5 found, from polarizing microscopy and X-ray diffraction measurement, that injection-molded polypropylene is composed of five layers, whose thickness changed according to molding conditions. They conjectured that the f...

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Structures and properties of injection moldings of crystallization nucleator‐added polypropylenes. I. Structure–property relationships

Fujiyama

Wakino

1991

J of Applied Polymer Sci

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SYNOPSISFlexural test specimens were injection-molded from polypropylenes added with 0.5 wt % of calcium carbonate, talc, p-tert-dibutyl-benzoic acid monohydroxy aluminum, or p -dimethyl-benzylidene sorbitol under cylinder temperatures of 200-320°C. Properties such as flexural modulus, flexural strength, heat distortion temperature, Izod impact strength, hardness, and mold shrinkage and higher-order structures such as crystalline texture, crystallinity, a*-axis-oriented component fraction, and degree of crystalline orientation were measured and structure-property relationships were studied. By the addition of crystallization nucleators, the flexural modulus, flexural strength, heat distortion temperature, hardness, and mold shrinkage were increased and Izod impact strength was decreased. The degrees of crystalline orientation such as the orientation fraction OF and c-axis orientation function fe were increased by the addition of nucleators. The degree of the increase was higher as the crystallization temperature was higher. Close relationships were observed between some properties and the degrees of crystalline orientation. I NTRODU CTlO NWhen crystallization nucleators are added to crystalline polymers, the following effects are exp e~t e d l -~: ( i ) improvement of transparency of molded articles, (ii) improvement of processing cycle or spinnability, (iii) improvement of rigidity of molded articles or filaments, (iv) improvement of dimensional precision, ( v ) improvement of gloss, and (vi) prevention of sink. As crystallization nucleators for polypropylene, talc, 4-6 aluminum salts of benzoic acids, 69 and dibenzylidene sorbitols 39697s0-l2 are especially effective and studies have been concentrated on them. This paper is concerned with studies on structures and properties and structure-property relationships of injection moldings of crystallization nucleatoradded polypropylenes. Polypropylene was fixed and effects of addition of talc, p-tert-dibutyl benzoic acid monohydroxy aluminum, or p -dimethylbenzylidene sorbitol, which are widely and frequently used and of calcium carbonate, which shows almost no nucleating effect and hence was used for comparison were studied. Nucleator content was fixed at 0.5 wt %. Flexural test specimens were injection-molded by varying cylinder temperature at 200-320°C.Properties such as flexural modulus, flexural strength, heat distortion temperature, Izod impact strength, hardness, and mold shrinkage and higherorder structures such as crystalline texture, crystallinity, a*-axis-oriented component fraction, and degrees of crystalline orientation were measured and relationships between flexural modulus, flexural strength, and mold shrinkage and degrees of crystalline orientation were studied.

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Controlling of higher order structure of polypropylene with a nucleating additive.

Cited by 4 publications

References 0 publications

Rf Plasma Polymerisation for the Improvement of Interfacial Adhesion between Glass Fibres and Polybutene-1

Rf Plasma Polymerisation for the Improvement of Interfacial Adhesion between Glass Fibres and Polybutene-1

Crystal orientation in injection molding of talc‐filled polypropylene

Structures and properties of injection moldings of crystallization nucleator‐added polypropylenes. I. Structure–property relationships

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