Poly(lactic acid)/Functionalized Silica Hybrids by Reactive Extrusion: Thermal, Rheological, and Degradation Behavior

The highly aromatic hyperbranched polyamide (HBPA) was synthesized and used as a modifier in order to enhance the physical performance of polylactic acid (PLA). The results showed that compared to the neat PLA, the tensile strength of the PLA/HBPA blends increased by 41.8%; fracture energy increased by 42.8% when the content of HBPA was 1.0 phr. The addition of HBPA can significantly improve the thermal deformation temperature of PLA. The polarized optical microscope images suggested that HBPA can act as a nucleating agent for PLA during the isothermal crystallization. This research indicated HBPA exhibits excellent reinforcing effect for PLA, due to the formation of hydrogen bonds and/or chemical crosslinking between HBPA and PLA.

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“…The zero‐shear viscosity ( η 0 ) values were calculated using the Cross model 33–35 . The η 0 was calculated according to Equation ():

η = \frac{η_{0}}{1 + {((), \frac{η_{0}}{τ} \cdot \overset{γ}{true})}^{1 - n}}

where η is viscosity, η 0 is zero shear viscosity,

\dot{γ}

is shear rate, and (1 − n) is the dimensionless exponent of the Cross model equation.…”

Section: Methodsmentioning

confidence: 99%

“…The zero-shear viscosity (η 0 ) values were calculated using the Cross model. [33][34][35] The η 0 was calculated according to Equation (2):…”

Section: Characterizationmentioning

confidence: 99%

Improvement of mechanical properties and heat distortion temperature of polylactic acid by highly aromatic hyperbranched polyamide

Sun

Huang

Jin

et al. 2022

J of Applied Polymer Sci

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“…In TE, designing the scaffold is the most important step in properly choosing the best processing method, conditions and raw materials to successfully achieve the application it is designed for. Thanks to extensive research over recent years we can choose from among many processing methods (electrospinning, freeze‐drying, molecular imprinting, etc) and understand how processing conditions may affect the scaffold 6–11 …”

Section: Introductionmentioning

confidence: 99%

Influence of elastin on the properties of hybrid PCL/elastin scaffolds for tissue engineering

Sánchez‐Cid

Perez‐Puyana

Jiménez‐Rosado

et al. 2021

J of Applied Polymer Sci

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Developing scaffolds by combining different polymers in order to improve the properties of the bare polymers has become an extensively applied practice. Polycaprolactone (PCL) is a synthetic polyester with outstanding properties for tissue engineering (TE), although it does have certain drawbacks that can be counteracted by combining it with other biopolymers. The biopolymer elastin is an essential functional component of the dermal extracellular matrix. Therefore, the aim of this work was to produce binary systems comprising a combination of PCL (16 wt/vol%) and different concentrations of elastin (2 and 4 wt/vol%) to evaluate how the protein affects the matrix. To this end, the morphological, physicochemical, mechanical and biological properties of the aforementioned scaffolds were further characterized, observing that PCL/elastin is a suitable mixture as it improves the wettability of PCL when combined with elastin (the contact angles were reduced from 102 to ca. 70°). In addition, mixing PCL with a small quantity of elastin (2%) improved the mechanical properties of PCL‐based scaffolds (Young's modulus increased from 36 to 69 MPa and the maximum stress increased from 11 to 34 MPa).

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“…The absorptions at 921 cm −1 (due to flexural CH bond vibration) correspond to the crystalline structure of PLA, [ 22,23 ] whereas the absorptions at 1180 (due to COC asymmetric stretching groups) and 956 cm –1 are representative of its amorphous phase. [ 24–26 ] Comparing with the pure PLA sample, all composited samples show decreased intensity of 921 cm −1 peak and noticeable incensement of the peaks at 956 and 1180 cm −1 , indicating a reduction of crystallinity. Especially, the absorbance of 921 cm –1 almost disappeared for the sample of PLA‐0.8 wt%, suggesting an increasing amorphous region in the nanocomposites.…”

Section: Figurementioning

confidence: 99%

Direct Preparation of High Thermal Stable PLA‐Based Nanocomposite via Extra‐Low Loading of In Situ Exfoliated Ultrathin MWW Zeolite Nanosheets

Zhang

Wang

Zhang

et al. 2020

Macro Materials & Eng

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Environmental pollution by extensive utilization of petrochemical-based polymers cannot be solved by landfill and incineration; the former leads to waste and deterioration of land resources, and the latter often generates greenhouse and toxic gases. More seriously, it has already been reported to change into microplastics and transfer from land to the sea in recent years. [1,2] As one of the promising environmental friendly polymers, Poly(lactic acid) (PLA) shows an immense potential in replacing non-degradable polymers due to the advantages of good renewability and biodegradability. [3] However, the high mobility of PLA polymer chain around its glass transition temperature T g leads to an inferior heat resistance with Vicat softening temperature (VST) of 55-65 °C [4-6] and such a non-ignorable disadvantage prevents it from spread applications in many vital fields, for example, food containers, household appliances, and auto parts. [7,8] Many efforts have been made to improve its heat resistance property but with unsatisfying resutls. For example, the VST of the PLA-based composites could only be raised to 60-80 °C by adding 20 wt% carbon nanofiber, [9] 20 wt% Rayon fiber, [10] and 40 wt% halloysite nanotube. [11] Recently, zeolites have been employed as the filler to modify the property of polymers. For example, zeolite 4A with an average particle size of 1-2 µm has been added into PLA to improve its mechanical properties. [12] However, to the best of our knowledge, the filling of zeolite was also ineffective for enhancing PLA heat resistance. Therefore, it is still a big challenge to improve the heat resistance of PLA-based materials to meet practical requirements. Essentially, the heat resistance of polymers could be improved by two ways, that is, a) limiting the mobility of PLA polymer chain, which is often expressed by increasing the T g or crystallinity, and b) increasing the stiffness by changing molecular chain structure, which can be accomplished by chemical reactions such as grafting or copolymerization. Since it is non-environmental-friendly or difficult to precisely control the structure of PLA through chemical reactions, the former method is commonly considered as the main method to improve the VST by blending PLA with various reinforcements. The lamellar precursors for MWW Poly(lactic acid) (PLA)-based nanocomposite incorporated with zeolite MCM-22 precursor at extra-low loading of 0.2-0.8 wt% is directly prepared by melt compounding and injection moulding method. The Vicat softening temperature raises up to >155 °C, much higher than that of pure PLA (63 °C), which is very beneficial for its application in many fields such as a container for hot food due to its environmentally friendly property. The high heat resistance property is believed to not be caused by the improvement of crystallinity and glass transition temperature but resulting from the obstruction of PLA polymer chain movement originating from >CO•••HOSi hydrogen bonding between PLA molecules and the in situ exfoliated MWW zeolite na...

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Poly(lactic acid)/Functionalized Silica Hybrids by Reactive Extrusion: Thermal, Rheological, and Degradation Behavior

Cited by 4 publications

References 36 publications

Improvement of mechanical properties and heat distortion temperature of polylactic acid by highly aromatic hyperbranched polyamide

Improvement of mechanical properties and heat distortion temperature of polylactic acid by highly aromatic hyperbranched polyamide

Influence of elastin on the properties of hybrid PCL/elastin scaffolds for tissue engineering

Direct Preparation of High Thermal Stable PLA‐Based Nanocomposite via Extra‐Low Loading of In Situ Exfoliated Ultrathin MWW Zeolite Nanosheets

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