Stress Whitening in Polyester Melamine Coatings

Theoretical background for an optical method is presented which makes it possible to distinguish unambiguously between voids and particles as light scattering sites in polymeric materials. Typical dependences of turbidity as a function of diameter of scattering elements, their volume fractions and also turbidity curves as a function of the wavelength of the incident light were calculated, based both on the Lorenz-Mie theory and the fluctuation theory. Such dependences calculated for polypropylene-containing voids on the one hand and particles, differing only slightly from the surrounding matrix in their refractive index, on the other hand, are markedly different. The most significant results are: (i) Turbidity is at least by two orders of magnitude larger for voids in comparison to embedded particles of ethylene-propylene (EPDM) rubber of the same size, concentration and at the same wavelength. (ii) The wavelength dependence of turbidity for EPDM particles and the inherent refractive index fluctuations in the polypropylene matrix is much steeper as compared to voids for all considered diameters (0.1-10 μm). Thus, the nature of stress whitening in complex polymeric materials can be determined from turbidity measurements.

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Influence of Stress Whitening Pretreatment on Cell Structure, Foaming Behavior, and Mechanical Properties of AN/MAA Copolymer Foam

Polymer-Plastics Technology and Engineering ◽

10.1080/03602550902994987 ◽

2009 ◽

Vol 48 (9) ◽

pp. 897-904 ◽

Cited By ~ 3

Author(s):

Ting Chen ◽

Guangcheng Zhang ◽

Rui Ma

Keyword(s):

Mechanical Properties ◽

Cell Structure ◽

Foaming Behavior ◽

Stress Whitening

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Stress whitening in polyethylene

Polymer ◽

10.1016/0032-3861(81)90372-4 ◽

1981 ◽

Vol 22 (12) ◽

pp. 1610-1612 ◽

Cited By ~ 24

Author(s):

B.W. Cherry ◽

Teoh Swee Hin

Keyword(s):

Stress Whitening

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Influence of Hot Compression Moulding of Biopolymer Filled Waste Granulate Biopolymer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.315.448 ◽

2013 ◽

Vol 315 ◽

pp. 448-452 ◽

Cited By ~ 19

Author(s):

M. Khairul Zaimy Abd Ghani ◽

Anika Zafiah Mohd Rus

Keyword(s):

Electron Microscopy ◽

Ductile Fracture ◽

Smooth Surface ◽

Compression Moulding ◽

Cooking Oil ◽

Minimum Deformation ◽

Sem Micrograph ◽

Stress Whitening ◽

Hot Compress ◽

Scanning Electron

Bio-monomer based on original cooking oil was mixed with the hardeners with different percentages of Waste granulate Biopolymer (WB) fillers which is 30, 40, and 50 % equivalent to weight of monomer to produce Biopolymer filled Waste granulate Biopolymer (BWB) by using hot compress moulding. The tensile strength of BWB is 0.33, 0.45 and 0.43 MPa, meanwhile value of Youngs Modulus is 11.00, 8.18 and 5.06 MPa for loading 30, 40 and 50 % respectively. From the Scanning Electron Microscopy (SEM) micrograph, BWB has two characteristic and classified as a brittle and ductile fracture of granular (shiny) texture or cleavage character with little yielding before the sample breaks. Furthermore brittle fracture is characteristic by rapid crack propagation and then ductile fracture with stress whitening zone, appears fibrous appearance is dull and it have very rough surface. This fracture has glassy smooth surface, flat, bright, shiny and minimum deformation.

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