Environmental Stress Cracking of Poly(3-hydroxibutyrate) Under Contact with Sodium Hydroxide

Farias, Rômulo Freitas; Canedo, Eduardo L.; Wellen, Renate Maria Ramos; Rabello, Marcelo S.

doi:10.1590/1516-1439.286114

Cited by 9 publications

(8 citation statements)

References 30 publications

(39 reference statements)

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“…This important mechanism of degradation is not often taken into account in the case of biodegradable polymers. One study by Farias et al [357] showed that sodium hydroxide may act as a strong stress cracking agent for PHBV copolymers, significantly affecting the mechanical properties. SEM imaging confirmed that catastrophic failure was associated with extensive surface damage.…”

Section: Mechanical and Other Effects On Biodegradable Polymer Degradationmentioning

confidence: 99%

Lifetime prediction of biodegradable polymers

Laycock

Nikolić

Colwell

et al. 2017

Progress in Polymer Science

441

346

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The determination of the safe working life of polymer materials is important for their successful use in engineering, medicine and consumer-goods applications. An understanding of the physical and chemical changes to the structure of widely-used polymers such as the polyolefins, when exposed to aggressive environments, has provided a framework for controlling their ultimate service lifetime by either stabilizing the polymer or chemically accelerating the degradation reactions. The recent focus on biodegradable polymers as replacements for more bio-inert materials such as the polyolefins in areas as diverse as packaging and as scaffolds for tissue engineering has highlighted the need for a review of the approaches to being able to predict the lifetime of these materials. In many studies the focus has not been on the embrittlement and fracture of the material (as it would be for a polyolefin) but rather the products of degradation, their toxicity and ultimate fate when in the environment, which may be the human body. These differences are primarily due to time-scale. Different approaches to the problem have arisen in biomedicine, such as the kinetic control of drug delivery by the bio-erosion of polymers, but the similarities in mechanism provide real prospects for the prediction of the safe service lifetime of a biodegradable polymer as a structural material. Common mechanistic themes that emerge include the diffusion-controlled process of water sorption and conditions for surface versus bulk degradation, the role of hydrolysis versus oxidative degradation in controlling the rate of polymer chain scission and strength loss and the specificity of enzyme-mediated reactions.

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Section: Mechanical and Other Effects On Biodegradable Polymer Degradationmentioning

confidence: 99%

Lifetime prediction of biodegradable polymers

Laycock

Nikolić

Colwell

et al. 2017

Progress in Polymer Science

441

346

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“…[2][3][4] Structural faults, thermal stress, lack of mechanical resistance, environmental stress, working temperature above tempering (which could lead to the phase transition) could be considered the main reasons for fracture and deformation failure of molded parts. [5][6][7] Nikforooz et al 8 have studied fatigue behavior of laminated glass fiber-reinforced polyamide. In contrast to the behavior of unidirectional laminates, glass/polyamide laminates had a superior fatigue resistance compared to the glass/epoxy composite.…”

Section: Introduction *mentioning

confidence: 99%

Injection molded part material failure analysis

Solomon¹,

Solomon²

2020

Rev.Roum.Chim.

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In this study, the causes of the failure of an injection-molded polyamide part were analyzed. The working conditions of injection-molded parts are very complex depending on: pressure, temperature, friction, corrosion, etc. and, consequently, they could fail due to different reasons. Microscopic characterization, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and FTIR spectroscopy were used for fracture analysis of defected parts. Mechanical testing (flexural modulus, torque and notched Izod impact test) was also considered for part failure analysis. This analysis suggests that the parts have failed because they were overloaded during assembly operation, and their material was harder (in a transition state between ductile and brittle) than the parts from normal production (in ductile state). Our investigations revealed that, due to plastic deformation at room temperature, Nylon 6 presents an unusual phase transformation. There are similarities between austenitic stainless steel and Nylon 6. Thus, it consists in the fact that their γ forms transform into α forms, due to an applied heat treatment or at room temperature as a result of an applied pressure (plastic deformation). In both situations, material became harder and then less resistant to applied physico-mechanical actions. In this particular case, an unusual local material hardening was observed due to a combined influence of two processes (cooling process, torque test), with a failure of the molded parts.

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“…PHB is inherently a non-toxic material and it is considered biocompatible, being used in medical applications like prosthesis, suture threats and devices for drugs release inside the human body [10][11] . The general uses of PHB in replacement of ordinary plastics are growing, including applications like packing and other short life products like cups and cutleries for fast food restaurants.…”

Section: Introductionmentioning

confidence: 99%

Photodegradation and Photostabilization of Poly(3-Hydroxybutyrate)

et al. 2016

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The present work is concerned with the photodegradation and photostabilization of poly(3-hydroxybutyrate) (PHB) biopolymer. Two commercial grades of PHB were investigated, containing of 4.0% and 6.2% of hydroxyvalerate (HV) comonomer, named PHB 1 and PHB 2 , respectively. Injection moulded specimens were exposed to ultraviolet radiation (UV-A) in the laboratory for periods of up to 12 weeks and then characterized by tensile testing, surface appearance, size exclusion chromatography (SEC), and scanning electron microscopy (SEM). The exposure to UV radiation caused great damaged on the surface color, reduction of molecular size and mechanical properties. The effects were more pronounced on PHB 2 , probably due a lighter surface color and less packed macromolecular structure which facilitates the transmission of light throughout the samples. Specimens of PHB 1 were also injected with the addition of a UV absorber and antioxidant, resulting in a higher UV stability of PHB, as shown by a low reduction in molar mass and better mechanical properties.

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Environmental Stress Cracking of Poly(3-hydroxibutyrate) Under Contact with Sodium Hydroxide

Cited by 9 publications

References 30 publications

Lifetime prediction of biodegradable polymers

Lifetime prediction of biodegradable polymers

Injection molded part material failure analysis

Photodegradation and Photostabilization of Poly(3-Hydroxybutyrate)

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