scholarly journals Improve the strength of PLA/HA composite through the use of surface initiated polymerization and phosphonic acid coupling agent

2011 ◽  
Vol 116 (5) ◽  
pp. 785 ◽  
Author(s):  
Tongxin Wang ◽  
Laurence C. Chow ◽  
Stanislav A. Frukhtbeyn ◽  
Andy Hai Ting ◽  
Quanxiao Dong ◽  
...  
Keyword(s):  
Phosphonic Acid ◽  
Coupling Agent ◽  
Surface Initiated Polymerization

scholarly journals How alkali-activated Ti surfaces affect the growth of tethered PMMA chains: a close-up study on the PMMA thickness and surface morphology

2019 ◽  
Vol 91 (10) ◽  
pp. 1687-1694
Author(s):  
Melania Reggente ◽  
Sebastien Kriegel ◽  
Wenjia He ◽  
Patrick Masson ◽  
Geneviève Pourroy ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Surface Morphology ◽  
Methyl Methacrylate ◽  
Phosphonic Acid ◽  
Coupling Agent ◽  
Alkali Activation ◽  
Oh Groups ◽  
Radical Polymerisation ◽  
Alkali Activated

Abstract The alkali-activation of titanium (Ti) surfaces performed in a heated sodium hydroxide (NaOH) aqueous solution, results in a porous layer rich in hydroxyl (OH) groups, the structure and porosity of which strongly depend on the reaction time and NaOH concentration used. In this study, a polymerization initiator is covalently grafted on the alkali-activated Ti substrates by using a phosphonic acid as coupling agent and the resulting surfaces are used as scaffolds to drive the growth of tethered poly(methyl methacrylate) (PMMA) chains via a surface initiated atom transfer radical polymerisation (SI-ATRP). A close-up investigation of how different treatment times (1 h, 3 h, 6 h, 12 h, and 24 h) and NaOH concentrations (0.1 M, 0.5 M, 1 M, 2 M, and 5 M) affect the final PMMA morphology and thickness are presented.

scholarly journals Phosphonic Acid Coupling Agent Modification of HAP Nanoparticles: Interfacial Effects in PLLA/HAP Bone Scaffold

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 199 ◽  
Author(s):  
Cijun Shuai ◽  
Li Yu ◽  
Wenjing Yang ◽  
Shuping Peng ◽  
Yancheng Zhong ◽  
...  
Keyword(s):  
Phosphonic Acid ◽  
Coupling Agent ◽  
Cell Attachment ◽  
Selective Laser Sintering ◽  
Acid Group ◽  
Interfacial Bonding ◽  
Esterification Reaction ◽  
Bone Scaffold ◽  
Phosphonic Acid Group ◽  
Sbf Solution

In order to improve the interfacial bonding between hydroxyapatite (HAP) and poly-l-lactic acid (PLLA), 2-Carboxyethylphosphonic acid (CEPA), a phosphonic acid coupling agent, was introduced to modify HAP nanoparticles. After this. the PLLA scaffold containing CEPA-modified HAP (C-HAP) was fabricated by selective laser sintering (frittage). The specific mechanism of interfacial bonding was that the PO32− of CEPA formed an electrovalent bond with the Ca2+ of HAP on one hand, and on the other hand, the –COOH of CEPA formed an ester bond with the –OH of PLLA via an esterification reaction. The results showed that C-HAP was homogeneously dispersed in the PLLA matrix and that it exhibited interconnected morphology pulled out from the PLLA matrix due to the enhanced interfacial bonding. As a result, the tensile strength and modulus of the scaffold with 20% C-HAP increased by 1.40 and 2.79 times compared to that of the scaffold with HAP, respectively. In addition, the scaffold could attract Ca2+ in simulated body fluid (SBF) solution by the phosphonic acid group to induce apatite layer formation and also release Ca2+ and PO43− by degradation to facilitate cell attachment, growth and proliferation.

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