Advances in toughened polymer materials by structured rubber particles
Graphical abstract
This paper reviews the state-of-the-art research progress of polymer materials toughened by structured rubbers. Various structured rubber toughening are introduced in detail. The relationship between the structure of rubbers and the properties of modified polymer materials, such as toughness, modulus and heat resistance, is discussed. The influence of the interface or interphase on these properties is highlighted. The future research endeavors and possible directions for further progress in this field are outlined.
Introduction
The toughening of polymer materials has been extensively studied over the past several decades because of its commercial importance [[1], [2], [3], [4], [5], [6]]. Some techniques have been and are currently being developed for improving the impact toughness of polymer materials to meet the demand of their practical applications. The most widely studied technique involves the development of a two-phase structure with the use of soft rubber as the dispersed phase [7,8]. The impact toughness of rubber-toughened polymer materials is mainly determined by the rubber phase and the interfacial adhesion between rubber and the polymer matrix. Initially, homogeneous rubber microparticle toughening was investigated for various polymer materials. In this process, the rubber toughening mechanism was gradually established. Overall, under loading, rubber microparticles concentrate stress and cavitate, which facilitates the crazing or shear yielding of polymer matrices around the rubber particles [[9], [10], [11], [12], [13]]. Currently, the toughening of polymer materials is being studied considering the design and control of rubber structures for improving the toughness or realizing the rigidity-toughness balance with minimal loss of the thermal property of polymer materials.
In this study, to provide a general understanding on rubber toughening, we first briefly introduce the classification of polymer materials that require toughening (Section 2), common strategies to improve the interfacial adhesion between rubber and polymer matrices (Section 3), and homogeneous rubber microparticle toughening (Section 4). Further, we present the latest development in structured rubber toughening in detail. According to their internal structure, spatial arrangement, and size, structured rubbers are divided into four groups: heterogeneous rubber microparticles (Section 5), oriented anisotropic rubber microparticles (Section 6), rubber nanoparticles (Section 7), and bimodal size distributed rubber particles (Section 8; refer Fig. 1). Heterogeneous rubber microparticles are further subdivided into one-matrix-core, multiple-matrix-core, one-filler-core, and multiple-filler-core rubbers; wherein the filler core is additional polymer component different from the matrix material. Oriented anisotropic rubber microparticles are subdivided into oriented rod-shaped and oriented flaky rubbers. Rubber nanoparticles are subdivided into spherical and fibrillar rubber nanoparticles. In each section, we discuss the relationship between structures of these rubbers and properties of modified polymer materials, including toughness, modulus, and heat resistance, with some typical examples. We also highlight the influence of interface or interphase on these properties. Finally, we outline future perspectives and possible novel research directions (Section 9).
Section snippets
Classification of polymer materials to be toughened
Various polymer materials have different chain entanglement density, chain stiffness, molecular weight, cross-linking density, crystalline degree, and crystalline form. These diversities lead to their different microscopic deformation modes (localized crazing, localized shear yielding and extensive shear yielding) and macroscopic mechanical behaviors (brittle fracture and ductile fracture) under impact loading [14,15]. Overall, brittle fracture is characterized by a linear load-deflection curve
Common strategies for improving interface adhesion
In order to toughen polymers successfully, good adhesion between polymer and rubber is essential because the deformation response of polymer matrix to rubber is realized through stress transfer at their interface. In this section, we will brief introduce the common strategies for improving the interfacial adhesion in rubber/polymer blends. Overall, the strategies to improve the interface adhesion are divided into adding compatibilizers [22], using reactive rubbers [[23], [24], [25]], and
Toughening by homogeneous rubber microparticles
Over the past several decades, homogeneous rubber microparticle toughening has been widely investigated for various polymer materials. Many reports focus on investigating the effect of rubber content and size on toughening. In this section, we will briefly introduce homogeneous rubber microparticle toughening, which involves rubber content, size, and the related toughening mechanisms. Generally, an increase in the rubber content would increase the toughness of polymer materials, which is
Toughening by heterogeneous rubber microparticles
Heterogeneous rubber microparticles are composite rubber particles with polymer inclusions. According to the property and number of inclusions, they are divided into four types: one-matrix-core, multiple-matrix-core, one-filler-core, and multiple-filler-core rubbers. The filler core is an additional polymer component different from the matrix material. If interfacial adhesion is good enough, the presence of one or multiple cores refines the size of the formed voids through fibrillation of the
Toughening by oriented rod-shaped rubbers
An oriented rod-shaped rubber is produced from spherical rubber/thermoplastic polymer blends by dynamic packing injection molding (Fig. 12a) [154,155]. Initially, the spherical rubber/thermoplastic polymer blend is melted and injected into a hot mold. Further, two pistons move reversibly with the same frequency, and they force the blend melt to move repeatedly in the mold cavity. The generated oscillatory shear stress promotes spherical rubber microparticles to elongate and orientate along the
Toughening by rubber nanoparticles
It is known that resistance to cavitation in rubber particles increases with the decrease in diameter. At the same time, the decrease in rubber diameter, especially down to nanoscale, dramatically increases their specific surface area (Fig. 14a). A large specific surface area would increase the stress transfer efficiency between the polymer matrix and rubber, and generate non-ignorable volume of interphase. In some cases, the interphase, which has different physical properties from the bulk of
Toughening by bimodal size distributed rubber particles
Bimodal size distributed rubber particles are the mixture of a type of large rubber particle and another type of small rubber particle. They toughen some glassy thermoplastic polymers synergistically, which are superior to the counterparts with large or small rubber alone. For example, Alfarraj et al. [282] blended 0.5āÆĪ¼m homogeneous PB rubber-toughened PS with 1.5āÆĪ¼m salami PB rubber-toughened PS. Its impact toughness was higher than the linear average of two unimodal rubber-toughened PS.
Conclusions and outlook
Developing a two-phase structure with soft rubber as the dispersed phase significantly improves the impact toughness of various polymers, such as glassy thermoplastic polymers, pseudo-ductile thermoplastic polymers, and thermosetting polymers. Essentially, the soft rubber particles concentrate stress and cavitate to generate voids in their interior, which facilitate multiple crazing of glass thermoplastic polymers and promote shear yielding of pseudo-ductile thermoplastic polymers and
Acknowledgments
We acknowledge the financial support from the High-level Innovative Talent Project in Hunan Province (2018RS3055), the National Natural Science Foundation of China (51973054, 51403008), and the Fundamental Research Funds for the Central Universities.
References (287)
- et al.
Largely improved toughness of PP/EPDM blends by adding nano-SiO2 particles
Polymer
(2007) - et al.
Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate-polymer composites
Compos Part B Eng
(2008) - et al.
Toughening mechanisms of nanoparticle-modified epoxy polymers
Polymer
(2007) - et al.
Toughening mechanisms in core-shell rubber modified polycarbonate
Polymer
(1990) - et al.
Detection of rubber particle cavitation in toughened plastics using thermal contraction tests
Polymer
(2000) - et al.
Microstructural processes of fracture of rubber-modified polyamides
Polymer
(1995) - et al.
Rubber toughening of practical tetraglycidyl methylenedianiline-piperidine adduct systems
Polymer
(1996) - et al.
Toughening of epoxy-based hybrid nanocomposites
Polymer
(2016) - et al.
Toughenability of polymers
Polymer
(2003) - et al.
Crystalline organization and toughening: example of polyamide-12
Polymer
(2005)
The influence of matrix modification on fracture mechanisms in rubber toughened polymethylmethacrylate
Polymer
Compatibilization of PBT/ABS blends by methyl methacrylate-glycidyl methacrylate-ethyl acrylate terpolymers
Polymer
Strategies for compatibilization of polymer blends
Prog Polym Sci
Reactions at polymer-polymer interfaces for blend compatibilization
Prog Polym Sci
Compatibilisation of heterogeneous acrylonitrile-butadiene rubber/polystyrene blends by the addition of styrene-acrylonitrile copolymer: effect on morphology and mechanical properties
Polymer
Improvement in toughness of poly(L-lactide) (PLLA) through reactive blending with acrylonitrile-butadiene-styrene copolymer (ABS): morphology and properties
Eur Polym J
Effect of compatibilization and ABS type on properties of PBT/ABS blends
Polymer
Elastomer particle morphology in ternary blends of maleated and non-maleated ethylene-based elastomers with polyamides: role of elastomer phase miscibility
Polymer
Compatibilizing effect of EPM-g-MA in EPDM/poly(trimethylene terephthalate) incompatible blends
Polymer
Rubber toughening of an amorphous polyamide by functionalized SEBS copolymers: morphology and Izod impact behavior
Polymer
Reactive processing of polymers: effect of in situ compatibilisation on characteristics of blends of polyethylene terephthalate and ethylene-propylene rubber
Polymer
Reactively compatibilised polyamide6/ethylene-co-vinyl acetate blends: mechanical properties and morphology
Polymer
Rubber toughening of nylon 6 nanocomposites
Polymer
Super-tough poly(lactic acid) materials: reactive blending with ethylene copolymer
Polymer
Influence of compatibilization on the mechanical behavior of poly(trimethylene terephthalate)/poly(ethylene-octene) blends
Eur Polym J
Impact behaviour of nylon-rubber blends: 4. Effect of the coupling agent, maleic anhydride
Polymer
Toughened poly(butylene terephthalate) by blending with a metallocenic poly(ethylene-octene) copolymer
Polymer
Ultimate mechanical properties of rubber toughened semicrystalline PET at room temperature
Polymer
Reactive processing of polymers: functionalisation of ethylene-propylene diene terpolymer (EPDM) in the presence and absence of a co-agent and effect of functionalised EPDM on compatibilisation of poly(ethylene terephthalate)/EPDM blends
Polym Degrad Stab
Crack-growth behavior of epoxy adhesives modified with liquid rubber and cross-linked rubber particles under mode I loading
Int J Adhes Adhes
Cure kinetics, morphology and miscibility of modified DGEBA-based epoxy resin - Effects of a liquid rubber inclusion
Polymer
Miscibility, morphology, thermal, and mechanical properties of a DGEBA based epoxy resin toughened with a liquid rubber
Polymer
Toughening mechanisms of rubber modified thin film epoxy resins
Prog Org Coat
Modification of epoxy resin using reactive liquid (ATBN) rubber
Eur Polym J
The mechanical properties and toughening mechanisms of an epoxy polymer modified with polysiloxane-based core-shell particles
Polymer
Toughening of poly(butylene terephthalate) with epoxy-functionalized acrylonitrile-butadiene-styrene
Polymer
The influence of core-shell structured modifiers on the toughness of poly (vinyl chloride)
Eur Polym J
Impact properties of acrylate rubber-modified PVC: influence of temperature
J Mater Process Technol
Effect of rubber-phase volume fraction in impact polystyrene on mechanical behaviour
Polymer
Polypropyleneārubber blends: 2. The effect of the rubber content on the deformation and impact behaviour
Polymer
Effect of core-shell rubber (CSR) nano-particles on mechanical properties and fracture toughness of an epoxy polymer
Polymer
Toughening behavior of rubber-modified thermoplastic polymer involving very small rubber particles: 1. A criterion for internal rubber cavitation
Polymer
Phase structure and adhesion in polymer blends: a criterion for rubber toughening
Polymer
Toughening mechanism of rubber-modified polyamides
Polymer
Brittle-tough transition in nylon-rubber blends: effect of rubber concentration and particle size
Polymer
Impact behaviour of nylon-rubber blends: 5. Influence of the mechanical properties of the elastomer
Polymer
Effect of Ī³-irradiation on brittle-tough transition of PBT/EPDM blends
Polymer
Deformation and toughness of polymeric systems: 7. Influence of dispersed rubbery phase
Polymer
Comparison of fracture behavior of nylon 6 versus an amorphous polyamide toughened with maleated poly(ethylene-1-octene) elastomers
Polymer
Comparison of the toughening behavior of nylon 6 versus an amorphous polyamide using various maleated elastomers
Polymer
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