Copolymers of 1,5-dioxepan-2-one and L- or D,L-dilactide: Hydrolytic degradation behavior

1994 ◽  
Vol 52 (9) ◽  
pp. 1327-1338 ◽  
Author(s):  
A. Löfgren ◽  
A.-C. Albertsson
Keyword(s):  
Hydrolytic Degradation ◽  
Degradation Behavior

scholarly journals Poly(-caprolactone)/graphene oxide composite systems: A comparative study on hydrolytic degradation at extreme pH values

2020 ◽  
Vol 10 (6) ◽  
pp. 892-902
Author(s):  
Alberto J. Campillo-Fernández ◽  
Pablo González-Reed ◽  
Ana Vidaurre ◽  
Isabel Castilla-Cortázar
Keyword(s):  
Graphene Oxide ◽  
Degradation Kinetics ◽  
Morphological Changes ◽  
Hydrolytic Degradation ◽  
Degradation Behavior ◽  
Composite Systems ◽  
Ph Values ◽  
Speed Up ◽  
Poly Caprolactone ◽  
Degradation Time

Polycaprolactone/Graphene oxide (PCL/GO) composites are shown to be promising substrates for tissue engineering as their degradation behavior is a key aspect in this type of application. The present paper studies the effect of different GO contents (0.1, 0.2 and 0.5 wt%) of PCL/GO composites on accelerated hydrolytic degradation at extreme pH values. Degradation kinetics at pH 13 is strongly affected by GO content, and speed up at higher percentages. The composite with 0.5 wt% of GO was completely degraded in 72 hours, while degradation at pH 1 presents a different profile and seems to have an induction period that lasts more than 1500 hours. Morphological changes, molecular weight distribution, weight loss, degree of swelling and calorimetric properties were investigated as a function of degradation time. According to the results obtained, the addition of small percentages of GO significantly influences the degradation behavior of the composites acting as degradation modulators.

scholarly journals Investigation of the Thermal and Hydrolytic Degradation of Polylactide during Autoclave Foaming

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2624
Author(s):  
Julia Dreier ◽  
Christian Brütting ◽  
Holger Ruckdäschel ◽  
Volker Altstädt ◽  
Christian Bonten
Keyword(s):  
Thermal Degradation ◽  
Hydrolytic Degradation ◽  
Reactive Extrusion ◽  
Foaming Properties ◽  
Twin Screw Extruder ◽  
Degradation Behavior ◽  
Screw Extruder ◽  
Melt Strength ◽  
Twin Screw ◽  
Good Potential

Polylactide (PLA) is one of the most important bioplastics worldwide and thus represents a good potential substitute for bead foams made of the fossil-based Polystyrene (PS). However, foaming of PLA comes with a few challenges. One disadvantage of commercially available PLA is its low melt strength and elongation properties, which play an important role in foaming. As a polyester, PLA is also very sensitive to thermal and hydrolytic degradation. Possibilities to overcome these disadvantages can be found in literature, but improving the properties for foaming of PLA as well as the degradation behavior during foaming have not been investigated yet. In this study, reactive extrusion on a twin-screw extruder is used to modify PLA in order to increase the melt strength and to protect it against thermal degradation and hydrolysis. PLA foams are produced in an already known process from the literature and the influence of the modifiers on the properties is estimated. The results show that it is possible to enhance the foaming properties of PLA and to protect it against hydrolysis at the same time.

scholarly journals Hydrolytic Degradation of Comb-Like Graft Poly (Lactide-co-Trimethylene Carbonate): The Role of Comonomer Compositions and Sequences

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2024
Author(s):  
Xuefei Leng ◽  
Wenwen Zhang ◽  
Yiying Wang ◽  
Yanshai Wang ◽  
Xiaoqing Li ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Hydrolytic Degradation ◽  
Gel Permeation Chromatography ◽  
Random Copolymers ◽  
Degradation Behavior ◽  
Weight Retention ◽  
Trimethylene Carbonate ◽  
Degradation Rates ◽  
Degradation Behaviors ◽  
Property Changes

The effect of sequence on copolymer properties is rarely studied, especially the degradation behavior of the biomaterials. A series of linear-comb block, gradient, random copolymers were successfully achieved using hydroxylated polybutadiene as the macroinitiator by simple ring-opening polymerization of l-lactide (l-LA) and 1,3-trimethylene carbonate (TMC). The hydrolytic degradation behaviors of the copolymers were systemically evaluated by using nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM) to illustrate the influences of comonomer compositions and sequence structures. The linear-comb block copolymers (lcP(TMC-b-LLA)) with different compositions had different degradation rates, which increased with l-LA content. Thermal property changes were observed with decreased Tm and increased ΔHm in all block copolymers during the degradation. To combine different sequence structures, unique degradation behaviors were observed for the linear-comb block, gradient and random copolymers even with similar comonomer composition. The degradation rates of linear-comb PLLA-gradient-PTMC (lcP(LLA-grad-TMC)) and linear-comb PLLA-random-PTMC (lcP(LLA-ran-TMC)) were accelerated due to the loss of regularity and crystallinity, resulting in a remarkable decrease on weight retention and molar mass. The hydrolysis degradation rate increased in the order lcP(TMC-b-LLA), lcP(LLA-ran-TMC), lcP(LLA-grad-TMC). Therefore, the hydrolytic degradation behavior of comb-like graft copolymers depends on both the compositions and the sequences dramatically.

Material design and photo-regulated hydrolytic degradation behavior of tissue engineering scaffolds fabricated via 3D fiber deposition

2017 ◽  
Vol 5 (2) ◽  
pp. 329-340 ◽  
Author(s):  
Ruixue Yin ◽  
Nan Zhang ◽  
Kemin Wang ◽  
Hongyu Long ◽  
Tianlong Xing ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Hydrolytic Degradation ◽  
Material Design ◽  
Degradation Behavior ◽  
Tissue Engineering Scaffolds ◽  
Fiber Deposition

A PLA/o-nitrobenzyl based scaffold was designed and fabricated by 3D fiber deposition to demonstrate the feasibility of photo-regulated hydrolytic degradation in vitro. It promises to approach the matched degradation with new tissues when applied in tissue engineering.

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