The effects of stress, environment and polymer variables on the durabilities of oriented polypropylene tapes

Horrocks, A. Richard; D'Souza, Jennifer A.

doi:10.1016/0141-3910(94)90050-7

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…Small holes are also observed, but it is not immediately obvious whether these are actual voids in the material or are etched out pockets where less resistant material has congregated. Voids have been found in other tapes after etching,14 but were not observed in the parallel work on the Milliken material.…”

Section: Resultsmentioning

confidence: 84%

“…The main features to note are the lines running across the section, which are much more abundant than in the parallel work on the Milliken material 4. Commercial and laboratory PP tapes are often found to be weak in this direction, giving rise to a raffia‐like fibrillation 14. In the present case, it is probable that the lines are (possibly incipient) cracks that have been opened up chemically by the etchant, as has been observed in some commercial fibers,3 although with careful preparation this weakness may be avoided 15.…”

Section: Resultsmentioning

confidence: 99%

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On morphologies developed during two-dimensional compaction of woven polypropylene tapes

Amornsakchai

Bassett

Olley

et al. 2000

J. Appl. Polym. Sci.

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The microstructure of compacted woven polypropylene cloths prepared at their optimum compaction temperature of 184°C has been examined. Details of transverse and longitudinal cross‐sections have been revealed by permanganic etching and observed with scanning electron microscopy. The original cloth was found to contain perpendicular cracks and biconical defects reported previously in other systems. After compaction, the cloth bonded together to form a thick solid sheet, with a melting point raised for the residual material but reduced for the recrystallized component. The higher melting regions form a continuous three‐dimensional network with linear traces in a longitudinal section, in agreement with recent observations of fiber structure. Recrystallization occurs both within and externally from tapes: where parallel tapes meet, transcrystalline layers emanate from tape surfaces, with a distinct line where the two growth fronts meet. In some more extensive recrystallized regions row structures are formed, probably indicating local flow during compaction. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 787–793, 2000

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

On morphologies developed during two-dimensional compaction of woven polypropylene tapes

Amornsakchai

Bassett

Olley

et al. 2000

J. Appl. Polym. Sci.

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“…Note that the presence of residual stresses introduced due to wrapping of the PP mesh around a glass rod may have contributed to their oxidative degradation resulting in corrosion stress cracking. The role of mechanical stress on the oxidative degradation of PP is non‐monotonous, and the rate, extent, and spatial distribution of oxidative degradation is affected by the combined roles of temperature, applied stress, oxidant concentration, relative humidity, and exposure time 56–59 . Therefore, the relative contributions of the elevated temperature, oxidative stress, and mechanical stress on the degradation of PP meshes could not be delineated in the current study.…”

Section: Resultsmentioning

confidence: 90%

Accelerated in vitro oxidative degradation testing of polypropylene surgical mesh

Jain,

Tantisuwanno,

Paul

et al. 2023

J Biomed Mater Res

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Polypropylene (PP) surgical mesh had reasonable success in repair of hernia and treatment of stress urinary incontinence (SUI); however, their use for the repair of pelvic organ prolapse (POP) resulted in highly variable results with lifelong complications in some patients. One of several factors that could be associated with mesh‐related POP complications is changes in the properties of the implanted surgical mesh due to oxidative degradation of PP in vivo. Currently, there are no standardized in vitro bench testing methods available for assessing the susceptibility to oxidative degradation and estimating long‐term in vivo stability of surgical mesh. In this work, we adapted a previously reported automated reactive accelerated aging (aRAA) system, which uses elevated temperatures and high concentrations of hydrogen peroxide (H2O2), for accelerated bench‐top oxidative degradation testing of PP surgical mesh. Since H2O2 is highly unstable at elevated temperatures and for prolonged periods, the aRAA system involves a feedback loop based on electrochemical detection methods to maintain consistent H2O2 concentration in test solutions. Four PP mesh samples with varying mesh knit designs, filament diameter, weight, and % porosity, were selected for testing using aRAA up to 4 weeks and characterized using thermal analysis, Fourier‐transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) and scanning electron microscopy (SEM). Additionally, the oxidation index (OI) values were calculated based on the FTIR‐ATR spectra to estimate the oxidative degradation and oxidation reaction kinetics of PP surgical mesh. The OI values and surface damage in the form of surface flaking, peeling, and formation of transverse cracks increased with aRAA aging time. The aRAA test method introduced here could be used to standardize the assessment of long‐term stability of surgical mesh and may also be adopted for accelerated oxidative degradation testing of other polymer‐based medical devices.

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“…The thermal properties of the filaments of specific interest due to their changes during degradation are heat of fusion (~Hf) [3], melt endotherm peak temperature (T max) [61, and degradation exotherm onset temperature ( Ton) [9,141. The heat of fusion gives a measure of the degree of crystallinity present, and Tmax, which is defined as the temperature at which crystallinity just persists [6], gives a measure of the regularity of the crystalline order: the higher the enthalpy of fusion, the higher the degree of crystallinity, and the higher Tma.,, the more orderly the macrolevels of polycrystalline order: Ton' on the other hand, gives a measure of the susceptibility to thermal oxidation and depends on the concentrations of oxidative centers present and hence degradation history [ 13].…”

Section: Filament Characterizationmentioning

confidence: 99%

Effect of Recycled Polyolefin Inclusion on the Properties of Polypropylene Filaments

Davies

Horrocks

2000

Textile Research Journal

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A series of polypropylene filaments containing a number of recycled polyolefins in varying concentrations are extruded in the absence and presence of a thermal stabilizer package. The physical and chemical properties of these filaments are then characterized to identify the effects of adding the recyclate. While the added recyclate affects the overall properties, there is a tolerance level up to which the changes may be accepted, and the magnitude of the overall effect depends on the physical and chemical properties of the recyclate.The need to increase the levels of recycling and reuse of polymers is a current concern, but despite research efforts to date [ 1,21,22], uses are limited to areas where properties are not critical. In areas where the products need' to be highly oriented, for example fibers, filaments and tapes, producers often introduce up to 10% by weight of their own process waste, since the demands of a high degree of chemical purity and physical order can be met by having a full knowledge of the recycled polymer being used. Commercially available recyclates have not been used for two reasons: first, if the history of a recycled polymer is not fully known, then the chemical purity and additive content cannot be guaranteed, and the presence of degradation products from oxidation and general polymer chain scission can adversely affect the properties of the derived filaments. Second, fibers and filaments used in textiles often undergo a coloration process at some stage, so the color of any recyclate becomes important. Due to environmental and economic pressures, however, polymer processors of technical textiles need to increase the levels of recycled polymer in their products. Some areas of technical textiles, for example geotextiles, where aesthetic properties are less important, would be an ideal outlet for recycled polymer, provided the derived filaments or tapes possess physical properties and durabilities comparable to those exhibited using virgin polymer only [28].In a recent study [11,12] of a laboratory-produced recycled polymer blended with virgin polymer for derived, oriented tapes, we have shown that there is an initial tolerance of up to 25% w/w recycled polymer before an unacceptable loss in tensile properties occurs. This increases to 75% w/w recycled polymer when an additional stabilizer is used. In this paper, we extend that earlier work to explore the effects of selected commercial recyclates on the physical and chemical properties of derived filaments. Experimental WorkRAw MATERIALS Five recycled polypropylene polymers (coded Ri to R5) were selected for this study. The physical properties of melt flow index (MH. g/10 min, 230°C, 2.16 kg). number-average molecular weight (Af~), weight-average molecular weight (M&dquo;.), and the polydispersity index (M&dquo;.lM&dquo;) of the recyclates and the virgin polymer (vPP) with which they were blended are given in Table I. M&dquo; M and Mn values were measured by gel permeation chromatography at RAPRA Technology, U.K. The virgin polymer was a...

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The effects of stress, environment and polymer variables on the durabilities of oriented polypropylene tapes

Cited by 12 publications

References 8 publications

On morphologies developed during two-dimensional compaction of woven polypropylene tapes

On morphologies developed during two-dimensional compaction of woven polypropylene tapes

Accelerated in vitro oxidative degradation testing of polypropylene surgical mesh

Effect of Recycled Polyolefin Inclusion on the Properties of Polypropylene Filaments

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