Glass Transition Temperature of Polymer–Nanoparticle Composites: Effect of Polymer–Particle Interfacial Energy

Chen, Fei; Clough, A. R.; Reinhard, Björn M.; Grinstaff, Mark W.; Jiang, Naisheng; Koga, Tadanori; Tsui, Ophelia Kwan Chui

doi:10.1021/ma4000368

Cited by 40 publications

(34 citation statements)

References 52 publications

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“…Therefore, some free volume spaces for the dangling polystyrene chains within matrices may be created as a resultant of MCM 41 nanoparticles aggregation which results in decrement of T g values. Numerous studies have dem onstrated that the glass transition temperature of poly mers can be changed upon addition of low content of nanoparticles [48,49]. In this context, reduction of T g values by increasing nanoparticles into the polymer matrix are plenty reported.…”

Section: Resultsmentioning

confidence: 99%

Spherical mesoporous silica nanoparticles/tailor-made polystyrene nanocomposites by in situ reverse atom transfer radical polymerization

et al. 2014

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Spherical mesoporous silica nanoparticles (MCM 41)/tailor made polystyrene nanocomposites were synthesized by in situ reverse atom transfer radical polymerization. Characteristics of spherical MCM 41 nanoparticles were evaluated by nitrogen adsorption/desorption isotherm and X ray diffraction. Morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight evaluations were carried out using gas and size exclusion chromatography respectively. Addition 3 wt% of MCM 41 nanoparticles results in a decrease in conversion from 89 to 53%. Similar reduc tion behavior is also observed for molecular weight of the nanocomposites. However, polydispersity indices (PDI) values increase from 1.42 to 2.07 by the only 3 wt% addition of MCM 41 nanoparticles. A peak around 4.1 ppm which originates from hydrogen atom of terminal units of polymer chains in 1 H NMR spectra in combination with low PDI values can appropriately demonstrate the living nature of the polymerization. Thermogravimetric analysis shows that thermal stability of the nanocomposites is higher than the neat poly styrene and increases by increasing MCM 41 nanoparticles content. Glass transition temperature decreases by the addition of MCM 41 nanoparticles loading as revealed by differential scanning calorimetry results.

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Section: Resultsmentioning

confidence: 99%

Spherical mesoporous silica nanoparticles/tailor-made polystyrene nanocomposites by in situ reverse atom transfer radical polymerization

et al. 2014

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“…A comparison of the results obtained by different authors reveals that the glass transition temperature of the composite is largely determined by factors such as: The production process (e.g., a sol‐gel method or a polymerization‐filling technique) . The method of stabilization of the nanoparticles in the polymer bulk (surface modification by low‐ or high‐molecular compounds) . The chemical structure of the nanoparticle surface, which provides the possibility of chemical bond formation and an adsorption interaction between the matrix and particle . The size of the particles and their aggregates . …”

Section: Introductionmentioning

confidence: 99%

Effect of hybrid nanoparticles on glass transition temperature of polymer nanocomposites

et al. 2015

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Changes in the glass transition temperatures of composites based on polystyrene and nanosized macromolecular nanostructures (molecular silicasols, dendrimers) are reported. Silicasols are nanosized particles consisting of a silica core and an ethyl phenyl shell; dendrimers are formed using a carbosilane core with ethyl phenyl end groups. It has been observed that the glass transition temperatures of the composites (T gc ) may be either above or below the glass transition temperature of polystyrene, depending on the size of the filler particles. A theoretical model based on the relation between the glass transition temperature and the configurational entropy of the composite, which satisfactorily describes the experimental dependence, was developed. It is found that the effect of the size of the hybrid nanoparticles on T gc was determined using two factors. First, the presence of an organic layer on the surface of nanoparticles increases the number of degrees of freedom and the entropy of the system, thereby reducing T gc . Second, the particles present in the polymer reduce the number of configuration states of macromolecules, which reduces the disorientation entropy. This effect leads to an increase T gc . The competition between these two main factors determines the sign of the glass transition temperature deviation. The size of the particles and their organic surface layer play the key roles in the thermodynamic properties of the composites. POLYM. COMPOS., 37:1978-1990

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“…In particular, ellipsometry studies 35 indicate that shifts from the bulk T g are the result of the interface (air/PS interface in PS films), viscosity measurements on thin films of low-M n PS have shown modifications even when the thickness is well above R EE , 36 and experiments with homopolymer brushes have shown that the amount of deviation is determined by the interfacial energy. 37,38 Thus, a simplified model, as shown in Scheme 2, for each block component consists of a region (V Int ) of finite size …”

Section: ■ Introductionmentioning

confidence: 99%

Controlling Macroscopic Properties by Tailoring Nanoscopic Interfaces in Tapered Copolymers

et al. 2015

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Systematic variation of comonomer concentration in individual polymer chains is responsible for unique phase behaviors in different types of copolymers. Controlled self-assembly of gradient copolymers into desired morphologies is theoretically understood but practically challenging, and identifying heterogeneous phase partitioning of individual comonomers in those resulting morphological regions can be difficult. Building on previous work where improved methods were used to elucidate heterogeneous comonomer partitioning in styrene−butadiene gradient copolymers [Clough et al. Macromolecules 2014, 47, 2625, the arrangement of the styrene and butadiene monomers in only a fraction of the total chain length is used here to significantly perturb the overall morphology and physical properties of copolymers. Importantly, the chemical composition of all copolymers was held nearly fixed in this study. The resulting tapered and inverse tapered block copolymers contain nanometer length scale interfaces that differ from one another and differ dramatically from that observed in a control block copolymer composed of chains with a discrete interface. Evidence is presented that butadiene can reside in rigid environments, styrene can reside in mobile environments, and their relative amounts can be varied based on the gradient design. The connection between the molecular design of the gradient, the resulting nanometer-length scale interfacial structures, and mechanical properties is demonstrated using a combination of variable temperature solid-state NMR, modulated DSC (differential scanning calorimetry), AFM (atomic force microscopy), and rheology experiments.

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Glass Transition Temperature of Polymer–Nanoparticle Composites: Effect of Polymer–Particle Interfacial Energy

Cited by 40 publications

References 52 publications

Spherical mesoporous silica nanoparticles/tailor-made polystyrene nanocomposites by in situ reverse atom transfer radical polymerization

Spherical mesoporous silica nanoparticles/tailor-made polystyrene nanocomposites by in situ reverse atom transfer radical polymerization

Effect of hybrid nanoparticles on glass transition temperature of polymer nanocomposites

Controlling Macroscopic Properties by Tailoring Nanoscopic Interfaces in Tapered Copolymers

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