Skip to main content

Controlled Oxidation of a Tetrafunctional Thiol to Obtain a Poly (Thiol- disulfide) Oligomer and Its Use as Self-healing Agent for Epoxy/Thiol-ene Photocurable Systems | Chapter 02 | New Advances in Materials Science and Engineering Vol. 2

In this work the pentaerythritol tetrakis (3-mercaptopropionate) was partially oxidized to obtain an oligomer with both thiol and disulfide functional groups in its structure, by using iodobenzene diacetate (IBDA) as oxidant. This oligomer was used to introduce disulfide bonds into the crosslinked network of a polyether-polythioether matrix obtained by photopolymerizing an epoxy/thiol-ene system. The presence of the disulfide bonds induced self-healing properties bonds in the obtained co-network. The oligomer was a joint component of the thiol-ene system along with a tetraallyl-functionalized ditertiary amine curing agent and a radical photoinitiator. The thiol groups of the oligomer reacted with the double bonds of the curing agent to form polythioethers, while the tertiary amine groups of the curing agent induced the anionic ring opening polymerization of the oxirane groups of an epoxy resin to produce polyethers. The kinetics of photopolymerization of the epoxy resin diglycidylether of bisphenol A (DGEBA), revealed that conversions of the epoxy groups as high as 80 % were achieved in only fifteen minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the co-network by using the thiol-disulfide oligomer, allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80 °C or for 500 minutes at room temperature. The analysis of mechanical properties using dynamic mechanical analysis (DMA) showed that the healed specimens, retained their mechanical properties depending on the amount of polythioethers present in the co-network.

Author(s) Details

Dr. Ricardo Acosta Ortiz
Centro de Investigación en Química Aplicada, Blvd Enrique Reyna #140, C.P. 25294, Saltillo, Coahuila, México.

View Book: http://bp.bookpi.org/index.php/bpi/catalog/book/123
Labels:

Comments

Post a Comment

Popular posts from this blog

A Prospective Study about Safety and Efficacy of Perioperative Lidocaine Infusion | Chapter 09 | New Horizons in Medicine and Medical Research Vol. 8

 Opioids cause clinically significant side effects such as respiratory depression, immunosuppression, muscle rigidity, negative inotropism, nausea, vomiting, hyperalgesia, urine retention, postoperative ileus, and drowsiness. Perioperative opioids are a major contributor to the United States' and other countries' opioid epidemics. Non-opioid analgesics, particularly lidocaine, are becoming more common for perioperative use as a result of this. A total of 185 adult patients were randomly assigned to one of two groups: control group I (105 patients) [fentanyl group] or group ii (80 patients) [opioid-free anaesthesia group]. Lidocaine 1.5 mg/kg bolus followed by 1.5 mg/kg/h infusion intraoperatively, and 1.5-2 mg/kg/h infusion for 2-8 hours postoperatively were given to patients in both groups at anaesthetic induction. Intraoperatively, both groups received analgesic adjuvants such as diclofenac 75 mg, paracetamol 1 gm, and mgso4 30-50 mg/kg. If the mean arterial pressure (map)
Post a Comment
Read more

A Brief Study of Middleware Technologies: Programming Applications and Management Systems | Chapter 15 | Novel Research Aspects in Mathematical and Computer Science Vol. 1

  Many platforms, services, applications, hardware, and operating systems are connected through the middleware layer. Because the middleware layer abstracts much low-level complexity and makes applications and software systems portable, it allows disparate systems to interface and function together in harmony. Middleware technologies enable software engineers to swiftly construct software systems and applications, allowing developers to focus on more important tasks. This chapter examines several types of middleware systems and discusses middleware capabilities, middleware operation, middleware's function in cloud-based systems, and the best middleware platforms to use. Middleware systems are widely utilised and can be found in practically any software system or application. Middleware programmes provide as a link between many sorts of systems and protocols. They serve as a mechanism for various systems. To successfully exchange information, it runs on a variety of operating system
Post a Comment
Read more

Patients’ Perspective of Acute Post-operative Pain Management: A Multicentre Survey of Tertiary Hospitals in Maharashtra, India | Chapter 08 | New Horizons in Medicine and Medical Research Vol. 8

 When postoperative pain is adequately controlled, patients' satisfaction and patient-related outcomes (PROs) increase. Understanding the patients' perspective is crucial since it supports in the formulation of improvement strategies. Because wrong attitudes and assumptions might block pain alleviation, patients' attitudes and beliefs are critical. As a result, a multicenter study of patients' attitudes, beliefs, experiences, and satisfaction levels with acute postoperative pain management was done in Maharashtra's tertiary hospitals. In addition, the responses were examined to evaluate if the Acute Pain Service (APS) resulted in improved patient outcomes and satisfaction. A 13-item questionnaire adapted from previous studies was used to capture patients' experiences with postoperative pain treatment. The responses of 179 patients are included in the study. The findings revealed that 91.6 percent of patients experienced postoperative pain, with 75.5 percent
Post a Comment
Read more