The chain dis-entanglement effect of polyhedral oligomeric silsesquioxanes (POSS) on ultra-high molecular weight polyethylene (UHMWPE)

Zhang, Xian; Zhao, Shicheng; Xin, Zhong

doi:10.1016/j.polymer.2020.122631

Cited by 35 publications

(21 citation statements)

References 37 publications

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“…31,39−41 Also, our analysis is limited to amorphous systems, while significant numbers of POSS composites are semicrystalline. 31,42,43 Lastly, this analysis is more powerful to predict T g a wide range of w POSS , approaching unity. In contrast, the classic Fox equation works well when the system lacks strong interactions between polymer matrix and POSS, such as hydrogen bonding.…”

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confidence: 73%

Rationalizing the Composition Dependence of Glass Transition Temperatures in Amorphous Polymer/POSS Composites

2021

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We report that the fractions of “bonded” or “unbonded” monomers at a filler interface dictate the composition dependence of the glass transition temperatures (T g) of polyhedral oligomeric silsesquioxane (POSS)-containing nanocomposites. T g is arguably the single most important material property; however, predicting T g in nanocomposites is often challenging because of confounding interfacial effects. To this end, we design a model nanocomposite to systematically study T g of nanocomposites by leveraging the “all-interfacial” nature of ultrasmall POSS fillers loaded into random copolymers of styrene and 2-vinylpyridine (2VP). The amine-functionalized POSS forms hydrogen bonds only with 2VP, which behaves as a “bonded” monomer. The influence of copolymer composition and POSS loading on the T g of this model composite is successfully explained by a Fox equation framework. This model also captures the T g increase of other POSS-based polymer composites and potentially directs the future design of nanocomposite materials with tailored T g.

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confidence: 73%

Rationalizing the Composition Dependence of Glass Transition Temperatures in Amorphous Polymer/POSS Composites

2021

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“…According to the elastic theory of rubber, the density of entanglement network can be characterized by the modulus of rubber platform when the system reaches thermodynamic equilibrium, and the influence of crystal structure has been eliminated in this time. In this study, the rubber platform area exists in temperature range of 160–200 °C, and Equations () and () 24,35–40 are often used to evaluate the entanglement molecular weight (

M_{e}

) and entanglement density (

v_{e}

) of UHMWPE. The entanglement molecular weight (

M_{e}

) refers to the average molecular weight between two entanglement nodes in UHMWPE chains.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, some researchers prepared composite materials by adding a small number of nanoparticles into UHMWPE to reduce the entanglement of UHMWPE. Zhang et al 24 studied the chain disentanglement effect of polyhedral oligomeric silsesquioxanes (POSS) on UHMWPE, and found that nanoparticles small enough could significantly alter the chain segment dynamics and chain relaxation process of the polymer, so that the entanglement degree of UHMWPE was reduced and the chain segment activity was increased. Xu et al 25,26 mixed multiwalled carbon nanotubes (MWNTs) into UHMWPE to gain low‐entanglement UHMWPE/MWNTs nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Regulating the dissolving system of ultra‐high molecular weight polyethylene to enhance the high‐strength and high‐modulus properties of resultant fibers

Wang

Song

et al. 2022

J of Applied Polymer Sci

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The molecular weight loss of ultra‐high molecular weight polyethylene (UHMWPE) fibers is extremely serious in comparison with raw materials due to the high temperature and strong shearing during dissolving process. In this study, decalin was introduced as preswelling solvent and the dissolving system was regulated to improve the solubility of UHMWPE in paraffin oil without severe degradation so as to prepare UHMWPE fibers with high molecular weight retention and low entanglement. UHMWPE was preswelling in decalin with different content, the mass ratio of decalin to UHMWPE were 1:1, 1.5:1, 2:1, 2.5:1, and 3:1. All UHMWPE fibers were prepared by gel‐spinning and hot‐drawing. UHMWPE fibers possess the highest molecular weight after preswelling of UHMWPE in decalin (with a mass ratio of 3:1 to UHMWPE, namely UPE/dec‐s‐3 sample). What's more, the entanglement of UHMWPE fibers gained from UPE/dec‐s‐3 sample has been observably diluted in comparation to that from UPE‐neat and other swollen samples. More importantly, the tensile strength and modulus of UHMWPE fibers obtained from UPE/dec‐s‐3 sample can reach 31.41 and 1446.26 cN/dtex, increased by 15.1% and 14.3% compared with UPE‐neat fibers, respectively. Besides, the thermal and crystallization behavior of UHMWPE fibers prepared from swollen UHMWPE have also been boosted.

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“…Considering that it is difficult to observe the plateau modulus (

) in the plots of storage modulus versus frequency in Figure 4 a, the plateau modulus (

) is obtained by van Gurp-Palmen (vGP) plot [ 21 ], and it is estimated by the following formula: G 0 = G*(ω) δ →min where δ is phase angle and G* is complex modulus.…”

Section: Resultsmentioning

confidence: 99%

Enhancing Chain Mobility of Ultrahigh Molecular Weight Polyethylene by Regulating Residence Time under a Consecutive Elongational Flow for Improved Processability

et al. 2021

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Improving the processability of ultrahigh molecular weight polyethylene (UHMWPE) and understanding the effect of the polymeric chain mobility has long been a challenging task. Herein, we show that UHMWPE without any processing aids can be processed at a lower temperature of 180 °C compared to conventional processing temperatures (~250 °C) under a continuous elongational flow (CEF) by using an eccentric rotor extruder (ERE). By probing the effect of the residence time of UHMWPE samples under a CEF on the morphology, rheological behavior and molecular orientation, we find that the long polymer chains of UHMWPE are apt to orientate under a consecutive volume elongational deformation, thereby leading to a higher residual stress for the extruded sample. Meanwhile, the residence time of samples can regulate the polymeric chain mobility, giving rise to the simultaneous decrease of the melting defects and residual stress as well as Hermans orientation function with increasing residence time from 0 to 60 s. This also engenders the enhanced diffusion of UHMWPE segments, resulting in a defect-free morphology and higher entanglement with lower crystallinity but without causing obvious thermal oxidative degradation of UHMWPE. This interesting result could originate from the fast chain entanglement and particle welding enabled by a desirably short residence time, which could be explained by the empirical, entropy-driven melting explosion mechanism.

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The chain dis-entanglement effect of polyhedral oligomeric silsesquioxanes (POSS) on ultra-high molecular weight polyethylene (UHMWPE)

Cited by 35 publications

References 37 publications

Rationalizing the Composition Dependence of Glass Transition Temperatures in Amorphous Polymer/POSS Composites

Rationalizing the Composition Dependence of Glass Transition Temperatures in Amorphous Polymer/POSS Composites

Regulating the dissolving system of ultra‐high molecular weight polyethylene to enhance the high‐strength and high‐modulus properties of resultant fibers

Enhancing Chain Mobility of Ultrahigh Molecular Weight Polyethylene by Regulating Residence Time under a Consecutive Elongational Flow for Improved Processability

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