Morphology characterization of high-impact resistant polypropylene using AFM and SALS

Swaminathan, K.; Marr, David W. M.

doi:10.1002/1097-4628(20001010)78:2<452::aid-app260>3.0.co;2-5

“…In addition to thin film study, there are also some reports on AFM investigations related to melt mixed polymer blend microstructures. , Blends of polypropylene (PP) with a compatible copolymer (such as ethylene−propylene (EP)) offer good interfacial and mechanical properties that permit micrometer and nanometer-scale structure investigations with AFM. − Investigation of the EP dispersed phase reveals a complex structure presenting amorphous and crystalline regions of different chemical natures. Galuska et al studied a variety of bulk polymer blends using AFM and samples prepared by microtomy.…”

Section: Introductionmentioning

confidence: 99%

High Contrast Imaging of Interphases in Ternary Polymer Blends Using Focused Ion Beam Preparation and Atomic Force Microscopy

and¹,

Favis²,

and³

et al. 2005

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In this paper, we demonstrate the applicability of focused ion beam (FIB) preparation followed by tapping mode atomic force microscopy (TMAFM) to analyze model interphase thicknesses in high density polyethylene/polystyrene/poly(methyl methacrylate) (HDPE/PS/PMMA) ternary polymer blends prepared by melt mixing. Previous work has shown that, in a polyethylene matrix, this blend exhibits a dispersed phase composed of a well-segregated PMMA core and a PS shell. Control of the PS/PMMA composition ratio allows for the control of shell thickness and hence this blend provides an excellent model system to analyze interphase thicknesses. A focused ion beam preparation was applied to the melt blended samples to prepare very smooth surfaces without mechanical deformation (i.e., no plowing or interfacial debonding), while TMAFM was used to obtain high-resolution images of the composite droplets in order to measure the mean diameter of the droplets and PS shell thickness. It is shown that the three polymer components have different ion beam etching rates, which results in a topological contrast between the phases of the blends when viewed by tapping mode atomic force microscopy. In this case, PMMA has the highest etching rate, while PS has the lowest and HDPE is intermediate. This high level of contrast between the phases allows for a clear identification of the PS interphase. Even the fine features of particles in the process of coalescing can be clearly identified. To ensure that this procedure was not altering the blend phase sizes in any way, average composite droplet diameters obtained with FIB preparation and TMAFM measurements were compared with the classic technique of cryomicrotome preparation and SEM measurements. The dispersed phase size data from the two procedures compare well. The FIB/TMAFM approach allows for the estimation of the PS interphase thicknesses from 100 to 200 nm depending on the PS/PMMA composition ratio. The approach presented here avoids the pitfalls associated with microtomy such as microvoiding, deformation of the materials and debonding at the interphase. It also eliminates the need for extraction of polymers with selective solvents and staining techniques used to provide contrast. This technique provides significant advantages for the analysis of multicomponent polymer blends or blends with complex morphologies. It also provides a first step toward a new approach for analyzing interphase thickness in polymer blends.

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Plastics Testing

Furches¹

2004

Kirk-Othmer Encyclopedia of Chemical Technology

1

0

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Plastics testing covers analytical, thermal, physical, and environmental procedures for determining the composition, structure, as well as mechanical and other responses to a variety of environmental conditions of plastic materials. General uses of Fourier transform infrared, nuclear magnetic resonance, Raman, and X‐ray techniques are reviewed and illustrated with specific examples. Developments in neutron and X‐ray scattering techniques, as well as molecular weight determination techniques such as gel‐permeation chromatography and turbidimetric methods, are also covered. Thermal tests, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and dynamic mechanical analysis are all useful for understanding degradation and phase changes in polymers and their influence on material behavior. New techniques of atomic force microscopy and positron annihilation are allowing studies of the microstructure of polymers and free volume determinations. Several mechanical testing techniques are used in plastics for normal quality control testing and initial application screening of polymers. These tests and those used for more fundamental understanding of polymer response to stress, including fracture mechanics procedures, are referenced. Flammability tests commonly used for plastics include oxygen index, flammability ratings, and smoke generation. Work on the use of cone calorimeters to characterize behavior of plastics under fire conditions is also covered. Finally, environmental testing, chemical exposure, weathering, radiation, and biological agents are reviewed. Emphasis is given to test development or applications reported since 1990.

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Test Methods

Furches

¹

2002

Encyclopedia of Polymer Science and Technology

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Plastics testing covers analytical, thermal, physical, and environmental procedures for determining the composition, structure, as well as mechanical and other responses to a variety of environmental conditions of plastic materials. General uses of Fourier transform infrared, nuclear magnetic resonance, Raman, and X‐ray techniques are reviewed and illustrated with specific examples. Developments in neutron and X‐ray scattering techniques, as well as molecular weight determination techniques such as gel‐permeation chromatography and turbidimetric methods, are also covered. Thermal tests, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and dynamic mechanical analysis are all useful for understanding degradation and phase changes in polymers and their influence on material behavior. New techniques of atomic force microscopy and positron annihilation are allowing studies of the microstructure of polymers and free volume determinations. Several mechanical testing techniques are used in plastics for normal quality control testing and initial application screening of polymers. These tests and those used for more fundamental understanding of polymer response to stress, including fracture mechanics procedures, are referenced. Flammability tests commonly used for plastics include oxygen index, flammability ratings, and smoke generation. Work on the use of cone calorimeters to characterize behavior of plastics under fire conditions is also covered. Finally, environmental testing, chemical exposure, weathering, radiation, and biological agents are reviewed. Emphasis is given to test development or applications reported since 1990.

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Morphology characterization of high-impact resistant polypropylene using AFM and SALS

Cited by 5 publications

References 15 publications

High Contrast Imaging of Interphases in Ternary Polymer Blends Using Focused Ion Beam Preparation and Atomic Force Microscopy

High Contrast Imaging of Interphases in Ternary Polymer Blends Using Focused Ion Beam Preparation and Atomic Force Microscopy

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