Thermoplastic polyurethane toughened polyacetal blends

Palanivelu, K.; Balakrishnan, S.; Rengasamy, Pichu

doi:10.1016/s0142-9418(98)00072-5

Cited by 48 publications

(36 citation statements)

References 8 publications

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“…POM-H cylinders are machined from the centre of an extruded bar to R a = 2.20 lm and are cleaned with acetone before sliding. POM-H shows linear decreasing strength between 80 and 110°C and keeps its favourable mechanical properties up to the heat deflection temperature of 92°C, as determined by Palanivelu [12] according to ASTM D 648. This temperature corresponds with a 50% decrease in tensile strength caused by gradual softening and thermal-oxidative degradation up to a melting temperature of 175°C.…”

Section: Test Materialsmentioning

confidence: 90%

“…This temperature corresponds with a 50% decrease in tensile strength caused by gradual softening and thermal-oxidative degradation up to a melting temperature of 175°C. The maximum operating conditions for POM-H as bearing material are limited to contact pressures of 70 MPa under static and 50 MPa under dynamic loading with a pv-limit of 0.16 MPa m/s under dry sliding [12]. The limiting pressure and pv-values will be exceeded in present high load tests (pv max = 0.75 MPa m/s).…”

Section: Test Materialsmentioning

confidence: 91%

“…The characteristics of the POM-H (Ertacetal H, Quadrant EPP) thermoplastic wear samples and steel counterfaces are given in table 1 [12]. POM-H cylinders are machined from the centre of an extruded bar to R a = 2.20 lm and are cleaned with acetone before sliding.…”

Section: Test Materialsmentioning

confidence: 99%

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Friction of polyoxymethylene homopolymer in highly loaded applications extrapolated from small-scale testing

Samyn

Baets

2005

Tribol Lett

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Most studies on tribology of polymer materials are traditionally performed on small-scale test specimens. However, to obtain data relevant for practical design of polymer parts in highly loaded bearings or sliding systems one must simulate real working conditions as close as possible on laboratory scale. In present work, a large-scale test rig has been used for determinating friction of a commercial polyoxymethylene homopolymer (POM-H). Test samples with contact area 22500 mm 2 are submitted to a reciprocating motion with stroke 230 mm under different contact pressures from 8 to 150 MPa and sliding velocity of 5 mm/s. Test results are compared to those obtained on a traditional cylinder-on-plate configuration and reveal lower friction on large-scale tests. However, general laws predicting the coefficient of friction as a function of normal loads cannot be used for extrapolation. Bulk and flash temperatures are calculated to explain transitions in friction mechanisms on both testing scales. Local surface temperatures are higher under large-scale sliding and allow for surface melting, which is not observed on small-scale tests. Although, sliding conditions implying an identical flash temperature induce polymer transfer only on large-scale tests, while no transfer occurs on small-scale tests. Even an artificial increase in small-scale bulk temperatures allowing for polymer transfer, is not able to provide low friction as observed on large-scale. An appropriate combination of load and sliding velocity is used for linear extrapolation of friction values, indicating the additional importance of bulk temperatures. When the polymer softening point is exceeded, creep at the polymer surface contributes to low friction.

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Section: Test Materialsmentioning

confidence: 90%

Section: Test Materialsmentioning

confidence: 91%

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Friction of polyoxymethylene homopolymer in highly loaded applications extrapolated from small-scale testing

Samyn

Baets

2005

Tribol Lett

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“…Several researchers [1][2][3][4][5][6][7][8][9][10][11][12][13] investigated the toughened POM/TPU blends focusing on physical properties, fracture behavior, and toughening mechanism. It was reported that the toughness of the POM/TPU blends depend on the concentration of TPU, [2][3][4]6,8,9,11 the interparticle distance of dispersed TPU phase 10,13 and the compatibility between POM and TPU. 12,13 With reagard to compatibilizers for the POM/TPU blends, Mehrabzadeh et al reported that 3% of diphenylmethane diisocyanate (MDI) in the POM/TPU (85/15 by weight) blend reduced the particle size of TPU and achieved the maximum impact strength, 12 and Gao et al reported that polystyrene-block-poly(ethylene-butylene)-block-polystyrene grafted with maleic anhydride (SEBS-graft-MA) enhanced the interfacial interaction between POM and TPU.…”

Section: Introductionmentioning

confidence: 99%

Interfacial reaction and its influence on phase morphology and impact properties of modified‐polyacetal/thermoplastic polyurethane blends

Kawaguchi¹,

Tajima²

2006

J of Applied Polymer Sci

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ABSTRACT:The cationic polymerization of 1,3,5-trioxane, 1,3-dioxolane and a small amount of 2-hydroxyacetic acid (HAA) was carried out, and the resulting modifiedpolyacetal (POM) was blended with thermoplastic polyurethane (TPU) in melt. The results of 1 H NMR analysis indicated that HAA was almost incorporated in the modified-POM, and that the resulting carboxyl end-group and hydroxyl end-group in the modified-POM reacted with TPU during the melt blending. There were many boundary layers between the cavities and matrix in the modified-POM/TPU (82/18 by weight) blend that was etched with tetrahydrofuran (THF), and the diameter of the cavities became ϳ0.3-1 m long when the blending time reached 10 min. The results of scanning electron microscopic (SEM) observation and dynamic mechanical analysis (DMA) indicated that the modified-POM/TPU blend had a good compatibility because of the interfacial reaction between the modified-POM and TPU phase in the blend. The modified-POM/TPU blend exhibited higher Charpy impact strength when compared with a normal-POM/TPU blend; the toughness of the modified-POM/TPU blend attributed to the good compatibility between the two phases.

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“…Literature data reveals that thermoplastic polyurethane is a useful toughening component for POM because of the signifi cant mutual physical interactions in the blend [51]. Palanivelu et al [52] used a twin screw extruder to obtain POM/TPU blends at four diff erent POM wt% of 90, 80, 70 and 60. Th ey revealed that tensile, fl exural and heat defl ection temperature of the blends decreases with the increase of TPU content, whereby notched Izod impact strength increased remarkably.…”

Section: Melt Extrusionmentioning

confidence: 99%

Polyoxymethylene Processing

Pielichowska¹

2014

Polyoxymethylene Handbook

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In this chapter major issues of polyoxymethylene (POM) and its nanocomposites processing are presented. Diff erent processing methods-injection molding, extrusion, blow molding, melt blowing, compression molding, rolling, sintering and spinning-as well as fabrication of highly oriented products, waste recycling, machining and assembling of moldings and semi-fi nished parts are described in regard to POM, which is an important engineering polymer used as structural material in all industrial sectors. However, processing of POM requires special attention since this polymer undergoes facile decomposition with evolution of formaldehyde. Some of the processing methods are for POM at infancy stage, such as electrospinning, due to poor solubility of this polymer in common solvents. Only recently has the successful electrospinning of polyoxymethylene nanofi bers with porous surface using a hexafl uoroisopropanol (HFIP)-based solvent been reported on. Polyoxymethylene types include impact modifi ed, fi lled and reinforced polymers in a wide range of sorts-this diversity may cause some problems during recycling by recompounding and remelting where extensive POM decomposition should be avoided because of formaldehyde release.

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Thermoplastic polyurethane toughened polyacetal blends

Cited by 48 publications

References 8 publications

Friction of polyoxymethylene homopolymer in highly loaded applications extrapolated from small-scale testing

Friction of polyoxymethylene homopolymer in highly loaded applications extrapolated from small-scale testing

Interfacial reaction and its influence on phase morphology and impact properties of modified‐polyacetal/thermoplastic polyurethane blends

Polyoxymethylene Processing

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