Studies on biaxial stretching of polypropylene film. IX. Melting behavior of biaxially stretched film in one step

Tanaka, Hiroshi; Masuko, Tōru; Okajima, Saburo

doi:10.1002/app.1973.070170606

Cited by 7 publications

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Studies on the biaxial stretching of polypropylene film. XI. Type II orientation during [2‐2FI]‐type stretching and its change by subsequent thermal contraction

Iwato¹,

Tanaka²,

Okajima³

1975

J of Applied Polymer Sci

View full text Add to dashboard Cite

SynopsisIn order to study the deformation mechanism of type I1 stretching, the change in orientation during the restretching and subsequent thermal contraction was investigated by x-ray daraction method. When a uniaxially oriented film is restretched, the lamellae which are stacked in the stretching direction by the stretching rotate as a whole toward the restretching axis. They rotate backward nearly reversibly during the thermal contraction, unless the restretching exceeds a balancing state, where the orientation in the film plane are equal in all directions. However, when the restretching degree is so high and the film orientation exceeds the balancing state, the lamellar rotation is accompanied by a complex phenomenon. It is considered from the wide-angle and small-angle x-ray diffraction patterns that the lamellar surface becomes indented because of slippage between microfibrils composing the lamellae, and the microfibrils themselves bend a t the boundary between the amorphous and crystalline regions within which the tilting of Caxis also occurs. Upon contracting of the film; these changes recover, but even in the last stage of contraction the orientation approaches the symmetrical biaxial orientation but not the uniaxial orientation from which the biaxial orientation is started. These orientation and disorientation behaviors are not affected basically by a slight change in the restretching temperature and the degree of stretching.Ia-' and type IIIIJJ were reported in the previous papers; hence, the orientation during type 11' stretching and its change due to subsequent thermal contraction are the subject of the present paper. It has been described' that [2-2FI]-type stretching, namely, stretching of a film with width unrestrained at temperature TI followed by restretching at temperature TZ perpendicularly to the stretching direction with insertion of a cooling pro-

show abstract

Studies on the biaxial stretching of polypropylene film. XI. Type II orientation during [2‐2FI]‐type stretching and its change by subsequent thermal contraction

Iwato¹,

Tanaka²,

Okajima³

1975

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

Biaxially oriented polypropylene blown films. I: Morphological analysis of orientation in the machine direction

Savolainen

1990

Polymer Engineering & Sci

View full text Add to dashboard Cite

In biaxial blown film technology of isotactic polypropylene, PP, the film tube drawn over the mandrel contains considerable morphological disorder. This disorder changes on further treatment to greater order i.e. the para‐crystallinity and the metastable crystal forms diminish as the monoclinic crystal form increases. The morphology change in PP was stimulated by further treatment of the drawn film tube over a mandrel corresponding to conditions of biaxial bubble forming. Analyses were by SEM, Wide‐angle X‐ray diffraction (reflection), DSC, and IR Dichroic measurements. A condenser quality PP, Mw/Mn = 7 and MFI = 3.7, shows a tensile yield at 110°C of 11.4 MPa. A tensile stress of 17.7 MPa was obtained at a blow up ratio of 7; the morphology of PP corresponds to deforming spherulites. The fraction of “perfectly” oriented molecules is 0.53.

show abstract

Melting behavior of highly stretched isotactic polypropylene film

Tanaka

Takagi

Okajima

1974

J. Polym. Sci. Polym. Chem. Ed.

View full text Add to dashboard Cite

Isotactic polypropylene film was stretched in poly(ethylene glycol) at 140°C and its melting behavior was investigated by using a differential scanning calorimeter (DSC‐1B). The shape of the melting curve depends largely on the stretching ratio, v. A sample stretched to moderate extension (1 < v < 3.5–4) has only a single melting peak (163°C) in the thermogram. When the sample is stretched beyond v = 3.5–4, the thermogram becomes more and more complex with increase of v, and some peaks appear when stretched to 10 < v < 13. The lowest peak which is considered to be the melting peak of the intermolecular crystals produced by the unfolding of chain molecules in the lamellae develops gradually with increase of v. In the thermogram for v = 18 the lowest temperature peak is most pronounced, in contrast to the highest temperature peak which decreases markedly in intensity. The phenomenon shows that large amounts of lamellar crystals are converted to intermolecular crystals in this region. On further stretching (v > 20) a very sharp high temperature peak appears, whose half‐width is about 1°C. Qualitatively similar results were obtained for the samples stretched in poly(ethylene glycol) at 150°C and in air at 140 and 150°C.

show abstract

Studies on biaxial stretching of polypropylene film. IX. Melting behavior of biaxially stretched film in one step

Cited by 7 publications

References 26 publications

Studies on the biaxial stretching of polypropylene film. XI. Type II orientation during [2‐2FI]‐type stretching and its change by subsequent thermal contraction

Studies on the biaxial stretching of polypropylene film. XI. Type II orientation during [2‐2FI]‐type stretching and its change by subsequent thermal contraction

Biaxially oriented polypropylene blown films. I: Morphological analysis of orientation in the machine direction

Melting behavior of highly stretched isotactic polypropylene film

Contact Info

Product

Resources

About