Rubber toughening

Rubber toughening is a process in which rubber nanoparticles are interspersed within a polymer matrix to increase the mechanical robustness, or toughness, of the material. By "toughening" a polymer it is meant that the ability of the polymeric substance to absorb energy and plastically deform without fracture is increased. Considering the significant advantages in mechanical properties that rubber toughening offers, most major thermoplastics are available in rubber-toughened versions;[1][2][3] for many engineering applications, material toughness is a deciding factor in final material selection.[4]

The effects of disperse rubber nanoparticles are complex and differ across amorphous and partly crystalline polymeric systems.[5] Rubber particles toughen a system by a variety of mechanisms such as when particulates concentrate stress causing cavitation or initiation of dissipating crazes.[6] However the effects are not one-sided; excess rubber content or debonding between the rubber and polymer can reduce toughness.[7] It is difficult to state the specific effects of a given particle size or interfacial adhesion parameter due to numerous other confounding variables.[6]

The presence of a given failure mechanism is determined by many factors: those intrinsic to the continuous polymer phase,[6] and those that are extrinsic, pertaining to the stress, loading speed, and ambient conditions.[8] The action of a given mechanism in a toughened polymer can be studied with microscopy. The addition of rubbery domains occurs via processes such as melt blending in a Rheomix mixer and atom-transfer radical-polymerization.[4][8]

Current research focuses on how optimizing the secondary phase composition and dispersion affects mechanical properties of the blend. Questions of interest include those to do with fracture toughness, tensile strength, and glass transition temperature.[9]

  1. ^ Bucknall, C. B. (1988). "The micromechanics of rubber toughening". Makromolekulare Chemie. Macromolecular Symposia. 20–21 (1): 425–439. doi:10.1002/masy.19880200145.
  2. ^ Zeidi, Mahdi; Kim, Chun IL; Park, Chul B. (2021). "The role of interface on the toughening and failure mechanisms of thermoplastic nanocomposites reinforced with nanofibrillated rubbers". Nanoscale. 13 (47): 20248–20280. doi:10.1039/D1NR07363J. ISSN 2040-3372. PMID 34851346. S2CID 244288401.
  3. ^ Zeidi, Mahdi; Park, Chul B.; Kim, Chun Il (2023). "Synergism effect between nanofibrillation and interface tuning on the stiffness-toughness balance of rubber-toughened polymer nanocomposites: a multiscale analysis". ACS Applied Materials and Interfaces. 15 (20): 24948–24967. doi:10.1021/acsami.3c04017. PMID 37172315. S2CID 258659550.
  4. ^ a b Fowler, M. W.; Baker, W. E. (1988). "Rubber toughening of polystyrene through reactive blending". Polymer Engineering and Science. 28 (21): 1427–1433. doi:10.1002/pen.760282112.
  5. ^ Liang, J. Z.; Li, R. K. Y. (11 July 2000). "Rubber toughening in polypropylene: A review". Journal of Applied Polymer Science. 77 (2): 409–417. doi:10.1002/(SICI)1097-4628(20000711)77:2<409::AID-APP18>3.0.CO;2-N.
  6. ^ a b c Walker, I.; Collyer, A. A. (2012). "Rubber toughening mechanisms in polymeric materials". Rubber Toughened Engineering Plastics. Springer Netherlands. pp. 29–56. doi:10.1007/978-94-011-1260-4_2. ISBN 9789401045490.
  7. ^ Bucknall, C. B. (1996). "Rubber Toughening of Plastics: Rubber Particle Cavitation and its Consequences" (PDF). Macromol. Symp. 101 (1): 265–271. doi:10.1002/masy.19961010130.
  8. ^ a b Kubiak, Joshua M.; Yan, Jiajun; Pietrasik, Joanna; Matyjaszewski, Krzysztof (19 May 2017). "Toughening PMMA with fillers containing polymer brushes synthesized via atom transfer radical polymerization (ATRP)". Polymer. 117: 48–53. doi:10.1016/j.polymer.2017.04.012.
  9. ^ Zhang, Jianing; Deng, Shiqiang; Wang, Yulong; Ye, Lin (1 January 2016). "Role of rigid nanoparticles and CTBN rubber in the toughening of epoxies with different cross-linking densities". Composites Part A: Applied Science and Manufacturing. 80: 82–94. doi:10.1016/j.compositesa.2015.10.017.