Mechanical Behavior of Filled Thermoplastic Polymers

Баженов, С. Л.

doi:10.5772/23316

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…All composites are ductile materials because ɛ b values in Figure 5(b) are mainly higher than limit fracture strain of 2–3%. 27 The simultaneous decrease of σ b and ɛ b values of composites with 8 vol% of polar silicas could be related to some additional factors discussed in tensile strength–spherulite size relationships.…”

Section: Resultsmentioning

confidence: 97%

“…On the other hand, ɛ b values of composites with nonpolar S-D17 and A-R8200 silicas and common characteristic of large spherulites 15 obey polynomial fitting satisfactorily. Unexpected increase of the ɛ b values at 8 vol% of nonpolar silica could be attributed to still regular spherulites 27 due to decreased nucleation ability of enlarged aggregates in the iPP matrix according to Zou et al. 28 On the other side, modified S-D17 microparticles and A-R8200 aggregates/agglomerates with finer dispersion than other silica fillers could be more suitably accommodated in interspherulitic regions 15 and with improved interactions with compatible iPP matrix.…”

Section: Resultsmentioning

confidence: 97%

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Interfacial and mechanical properties of polypropylene/silica nano- and microcomposites

Pustak

Leskovac

Denac

et al. 2014

Journal of Reinforced Plastics and Composites

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Various silica grades differing in particle size (micro- versus nanosilica) and surface modification (untreated versus modified surface) have affected interfacial and mechanical properties of compression-molded polypropylene composites with 2, 4, 6, 8 vol% of added silica. Mechanical properties have been influenced primarily by combination of stiff fillers and tough polypropylene matrix and additionally by restructured matrix. Namely, silica particles with different surface properties have influenced nucleation and spherulite growth differently affecting thus tensile properties of the composites. All composites exhibited best tensile strength in silica content range 2–6 vol%.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 97%

Interfacial and mechanical properties of polypropylene/silica nano- and microcomposites

Pustak

Leskovac

Denac

et al. 2014

Journal of Reinforced Plastics and Composites

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“…If molecular ordering in the specimens subjected to loading during degradation was higher than that in other groups, the mechanical properties could have been increased as the result of the creep process. 29 At the intermediate degradation time point studied here, the application of tensile load to PLGA did not result in alterations to the chemical degradation of the material (i.e., changes in molecular weight). This is consistent with limited observations in the literature that mechanical loading does not affect the rate of molecular weight loss.…”

Section: Discussionmentioning

confidence: 99%

Creep loading during degradation attenuates mechanical property loss in PLGA

Dreher

Nagaraja

2014

J Biomed Mater Res

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While absorbable materials and medical devices primarily degrade through hydrolysis, their degradation kinetics are sensitive to environmental conditions, including temperature, pH, and mechanical loading. While there is some consistent information in the literature suggesting that strain controlled loading accelerates strength loss, there is much more limited information on the interaction between degradation and mechanical load applied under force control. Force control conditions impose a different stress state on the material and therefore, may exhibit different effects on degradation. In this study, the interaction between loading and degradation rate for an exemplary absorbable polymer, poly(l‐lactide‐co‐glycolide), was investigated. The results indicated that load during degradation results in significant polymer creep, which is associated with increased force loss, but decreased strength loss (i.e., stress based parameters such as ultimate stress). This study further identified that changes to the degradation kinetics from exposure to loading were not associated with alterations to polymer crystallinity but were associated with delayed loss of molecular weight. Overall, these results demonstrate the importance of investigating the interaction between loading and degradation and that physical changes, such as those induced by creep, rather than chemical changes offer the strongest explanation for alteration of degradation kinetics. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 700–708, 2015.

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“…This change in the molecular structure results in the decrease in crystallinity of PLA, which in turn decreases the load-bearing capacity or the tensile strength of the PLA/EVA blend. Moreover, EVA is an elastomeric, so it absorbs the impact energy and acts as stress concentrator [44]. It impedes the crack initiation and propagation due to which the toughness of PLA/EVA blend increases.…”

Section: Mechanical Testingmentioning

confidence: 99%

Optimize PLA/EVA Polymers Blend Compositional Coating for Next Generation Biodegradable Drug-Eluting Stents

Ishaque

Naseer²,

Abbas

et al. 2022

Polymers

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In this research work, polymer blends of poly-lactic acid (PLA)/ethylene vinyl acetate (EVA) were prepared as the drug carrier materials for a bi-layer drug-loaded coating film for coronary stents. Different optimum compositions of blends were prepared by using an intense mixer. Then, the blends were hot-pressed and later cold-pressed to prepare for films of different thickness. The changes in weight, surface analysis and biodegradability with increasing time were studied using Scanning electron microscopy (SEM), weight loss and biodegradability tests. The mechanical and thermal properties of drug-loaded films were studied through universal testing machine (UTM) and thermo-gravimetric analysis (TGA). The effects of PLA, EVA and drug contents on in-vitro drug contents were investigated through the Ultraviolet-Visible Spectroscopy (UV-VIS) chemical analysis technique. The results obtained clearly showed that the addition of PLA promoted the unleashing of the drug whereas the addition of EVA nearly did not have the same affect. The mechanical properties of these various films can be tuned by adjusting the contents of blend parts. The factors affecting the unleashing of the drug became a serious matter of concern in evaluating the performance of bio-resorbable drug eluting stents. As a result, today’s chemical blends may be useful drug carrier materials for drug-loaded tube coatings capable delivering purgative drug in an incredibly tunable and regulated manner.

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Mechanical Behavior of Filled Thermoplastic Polymers

Cited by 4 publications

References 14 publications

Interfacial and mechanical properties of polypropylene/silica nano- and microcomposites

Interfacial and mechanical properties of polypropylene/silica nano- and microcomposites

Creep loading during degradation attenuates mechanical property loss in PLGA

Optimize PLA/EVA Polymers Blend Compositional Coating for Next Generation Biodegradable Drug-Eluting Stents

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