Increase In Molecular Weight Research Articles

Secondary Organic Aerosol Formation from Semi-Volatile and Intermediate Volatility Organic Compounds in the Fall in Beijing

Intermediate volatility organic compounds (IVOCs) and semi-volatile organic compounds (SVOCs) have recently been proposed as important precursors of secondary organic aerosol (SOA). In the present work, 97 volatile organic compounds (VOCs) and 80 intermediate volatility and semi-volatile organic compounds (IVOCs and SVOCs) were measured by online gas chromatography-mass spectrometer/flame ionization detection (GC-MS/FID), and offline thermal desorption gas chromatography-mass spectrometer (TD-GC-MS), respectively. The average concentration of speciated VOCs, IVOCs, and SVOCs were 22.36 ± 9.02 μg m−3, 1.01 ± 0.32 μg m−3, and 0.10 ± 0.17 μg m−3. Alkanes and polycyclic aromatic hydrocarbons (PAHs) are the main compounds of total S/IVOCs. With the increase in molecular weight, the concentrations decreased in the gas phase, while increasing in the particle phase. Vehicular emission is the most significant source according to the carbon preference index (CPI) and the carbon of the most abundant alkane (Cmax). The yield method was used to estimate SOA from the oxidation of VOCs and S/IVOCs. The estimated SOA mass from IVOCs and SVOCs (0.70 ± 0.57 μg m−3) was comparable to that of VOCs (0.62 ± 0.61 μg m−3), and the oxidation of PAHs and alkanes took up 28.70 ± 8.26% and 51.97 ± 20.77% of the total SOA estimation, respectively. Compared to previous work, our study provided detailed molecular information of ambient S/IVOC species and elucidated their importance on SOA formation. Despite their low concentration, S/IVOCs species are important SOA precursors which shared comparable contribution compared with VOCs.

Geochemistry of Soils from the Surrounding Area of a Coal Mine Waste Pile Affected by Self-Burning (Northern Portugal)

Coal mining can generate organic and inorganic contaminants that can be disseminated in the surrounding soils by leaching and/or aerial deposition. This study aims to identify and characterize the physicochemical and geochemical changes promoted in soils from the surrounding area of a self-burning waste pile in an abandoned coal mine. A soil sampling campaign was conducted bordering the waste pile, comprising the main drainage areas as well as the areas uphill. The soils were characterized geochemically for major and trace elements and multivariate statistics was used in combination with geostatistical methodologies to study the statistical and spatial relations of the different elements and infer their Potentially Toxic Elements (PTEs) sources. The 16 priority Polycyclic Aromatic Hydrocarbons (PAHs) were identified and quantified in soils according to their spatial distribution, and their pyrogenic/petrogenic sources were inferred. Different sources were identified as contributing to the soil geochemical signature, considering not only the mine but also anthropogenic urban contamination or naturally enhanced regional geochemical background in multiple PTEs. PAHs tend to concentrate downstream of the waste pile, along the runoff areas, presenting a greater variety of the 16 priority PAHs and an increase of High Molecular Weight (HMW) PAHs pointing to its pyrogenic origin, possibly related to the self-combustion phenomenon occurring in the waste pile.

Electro-nanofiltration membranes with high Li+/Mg2+ selectivity prepared via sequential interfacial polymerization

With the rapid development of batteries and other industries, the demand for lithium has exploded. As about 70 wt% of the lithium resources exist in brines, the extraction of lithium by selective electrodialysis (S-ED) has attracted extensive attention. However, the similar hydrated ionic radius of Li+ and Mg2+ caused many challenges. Herein, a simple sequential interfacial polymerization (SIP) method was developed to adjust the surface charge and pore size of the electro-nanofiltration membranes (ENFMs), and the ENFMs were endowed with excellent selectivity due to the electrostatic repulsion and pore-size sieving effect. Polyethyleneimine (PEI) with different molecular weights was used for the SIP process based on the nascent polyamide separation layer prepared by interfacial polymerization. With the increase of the PEI molecular weight, the zeta potential of the membrane surface changed from negative to positive, while the pore size of the membranes also decreased. The optimal ENFMs achieved outstanding selectivity for Li+/Mg2+ (16.55) and high Li+ flux (3.08 × 10−8 mol·cm−2·s−1) at a current density of 10 mA·cm−2. Moreover, the optimal ENFMs exhibited high limiting current density (50.6 mA·cm−2) and low membrane electrical resistance (2.42 Ω·cm2), which has a great potential to be used for practical applications.

Modelling of Propylene Polymerization in a Loop Reactor on the Titanium–Magnesium Catalyst Taking into Account the Transformation of Active Centers

The volume of consumed and produced polymers is increasing in the market every day. This is due to the indispensability and convenience of polymers in all industries. The article presents the distinctive features of the use of titanium–magnesium catalysts in the process of propylene polymerization. A mathematical model of the polypropylene polymerization is presented. This model is the basis of creating an expert control complex of the propylene–ethylene block copolymer (PEBC) synthesis process and allowing a quantitative connection to be made between technological parameters of reactors, which allows control of the technological mode with the acceptable accuracy. The experiment catalytic system is microspheric titanium trichloride (MS-TiCl3) and co-catalyst-diethylaluminum chloride. Dependences of different parameters on others are illustrated. The result of the research is as follows: according to the calculations, when increasing the number of blocks in the chain, the average values of molecular weights increase and the polydispersity index decreases; changing the values of the transformation rate coefficients of active centers by the donor k 12 and k 21 allows research into the effect of the donor type.

Influence of Molecular Weight on the Bead Foaming and Bead Fusion Behavior of Poly(butylene terephthalate) (PBT)

A current trend in the progress of bead foams is the use of engineering polymers (i.e., poly(butylene terephthalate) (PBT)), which are more temperature resistant than commodity polymers and thus offer new areas of application. Currently, foaming and molding of PBT bead foams seem to be possible only with an epoxy-based chain extender. This modification leads not only to an increase in molecular weight but also to a changed PBT chain architecture (i.e., branching or even cross-linking). Thereby, the crystallization behavior is considerably slowed down so that the time for chain interdiffusion across neighboring bead surfaces is prolonged. This study investigates the molecular weight influence separately. The crystallization behavior is controlled by varying the length of linear PBTs in such a way that different bead fusion phenomena result. With increasing molecular weight, a lower open cell content (OCC), and therefore a higher expansion behavior during thermomechanical analysis, was observed, which increases the contact area between the beads in the cavity during the steam chest molding process. Adding to the literature shown so far, this study shows that linear chemically unmodified PBT can also be processed into bead foam components using PBTs having a higher molecular weight.

Effect of deacetylation degree and molecular weight on surface properties of chitosan obtained from biowastes

A surface characterization of two types of unmodified chitosan properties with different molecular weight (MW) and deacetylation degree (DD) was carried out in terms of polymer concentration (a concentration lower than the saturation, the saturation concentration and a supersaturated concentration). The modification of the production conditions allowed to obtain chitosan samples with different properties (MW and DD), which eventually determined its surface activity. Thus, a kind of tailor-made chitosan may be designed to be adapted to different applications. Surface activity has been analysed by mean of measurements of surface tension, dilatational and shear rheology. The results have demonstrated that chitosan possessed a good surface activity at high ionic strength. Also, the increase in the concentration of chitosan in the solution, and the increase in molecular weight (and, therefore, a decrease in the degree of deacetylation) favoured the formation of aggregates, which improved the adsorption kinetics. The latter allowed adequate elasticity values to be reached more quickly. These properties are reached faster for the higher molecular weight chitosan (lower degree of deacetylation), due to the more hydrophobic character that facilitates the interactions between the adsorbed aggregates. Surface rheology revealed a predominantly elastic behaviour of chitosan film. All of these results strengthen the idea that chitosan behaves as a surface-active hydrophilic Pickering agent.

Impact of Process Poisons on the Performance of Post‐Phthalate Supported Ziegler–Natta Catalysts in Gas Phase Propylene Polymerization

AbstractThe impact of common process catalyst poisons on the performance of a 6th generation Ziegler–Natta catalysts during the gas phase polymerization of propylene are examined using two approaches: introducing propylene without purification, or with one or two sets of purification columns, and by introducing carbon dioxide (CO2), oxygen (O2), water (H2O), methanol (CH3OH), ethyl acetate (C4H8O2) and dimethyl sulfoxide (C2H6SO) during the polymerization. As expected, purification columns increases the catalyst activity significantly, slightly reduce catalyst decay. Injecting TiBA during the reaction leads to an activity increase. The addition of two full sets of columns substantially increased the repeatability of polymerization reactions. The power of deactivation of poisons injected during the polymerization reaction is: O2 > CO2 > CH3OH > C2H6SO > C4H8O2 > H2O. Adding CO2, O2, and CH3OH resulted in a progressive decrease in molecular weight while almost no effect is observed with H2O. However, C4H8O2, and C2H6SO resulted in a mild increase in molecular weight. Additionally, the effects on crystallinity and stereoregularity are similar where CO2, O2, H2O and CH3OH caused a progressive decrease while C4H8O2 and C2H6SO resulted in a mild increase, indicating some isotacticity control by these two poisons.

The effect of quaternary ammonium salts with different chain lengths on copper filling behavior in blind holes of printed circuit board

The rapid and defect free blind hole copper super filling is the key technology to ensure the quality and development of printed circuit boards (PCBs). The linear quaternary ammonium compounds with a low molecular weight are expected to act as a potential suppressor for blind hole copper filling. Here, three quaternary ammonium salts with different molecular chain lengths (the dodecyl trimethyl ammonium chloride, the cetyl trimethyl ammonium chloride and the stearyl trimethyl ammonium chloride) were selected to study the effects of the molecular chain length of quaternary ammonium salt on the copper filling behavior of the PCB blind holes. The electrochemical results show that the three quaternary ammonium salts show greater inhibition ability on copper deposition compared with the traditional additives (polyethylene glycol (PEG) and Cl−) and furthermore, the suppressor effect becomes stronger with the increase of molecular weight. The blind hole copper filling experiment of PCB is also carried out to study the copper filling capacity of three quaternary ammonium salts. The filling experiment reveals that compared with the traditional suppressors (PEG and Cl−), the filling quality of blind hole copper is significantly improved when the three quaternary ammonium salts are used as suppressors. Moreover, under the coordination of accelerator (bis (3-sulfopropyl) disulfide (SPS)), the three quaternary ammonium salts can realize more rapid copper super filling without chloride ion in the electrolyte. Cross-section and surface morphological analysis further illuminates that the quaternary ammonium salt as an suppressor can also more effectively inhibit the deposition of copper on the PCB surface and reduce the roughness of the copper layer. The present results imply that quaternary ammonium salts have greater advantages for copper filling and are expected to replace traditional suppressors as new suppressors.

Effect of hyperbranched poly(trimellitic glyceride)/oxidized starch composite sizing agent on the adhesion of polyester yarns

AbstractOxidized starch is an environmentally friendly sizing agent, but lacks adhesion to polyester yarns. In this study, hyperbranched poly(trimellitic glyceride)/oxidized starch (PTG/OS) as the composite sizing agent is used for sizing polyester yarns. The properties of sizing film, sizing paste, and sizing yarns are studied. When PTG content ranges from 2 to 10 wt%, tensile strength of PTGs/OS films are higher than that of oxidized starch film, and increase as molecular weight of PTG increase. Tensile strength of OS, PTG‐1/OS, PTG‐2/OS, and PTG‐3/OS films with 10 wt% PTG is 20.5, 22.4, 23.8, and 27.6 MPa, respectively. Apparent viscosity and viscosity stability of PTG/OS paste increases with the increase of PTG molecular weight. Breaking force, elongation at break and work‐to‐break of sizing polyester yarns by PTG/OS increase with the increase of PTG content in composite sizing agents, and the improvement on the tensile properties of sizing polyester yarns by PTG/OS becomes better with increase of PTG molecular weight. It is attributed to the stronger affinity among oxidized starch, PTG and polyester, which is verified by FT‐IR, XPS, and SEM. Oxidized starch blended hyperbranched poly(trimellitic glyceride) has the potential application for sizing polyester yarns in weaving process.

Interaction of operating HRT and temperature on fouling of tertiary membranes treating municipal wastewater

This paper presents the first study to quantify and demonstrate the interactions between SBR operating conditions (hydraulic retention time (HRT) and temperature) and soluble microbial product (SMP) generation, as well as the impact of SBR operating conditions and filtration temperature on fouling of membranes used in tertiary treatment. Reducing SBR operating HRT from 20 to 10 h resulted in an increase in SMP concentrations, however, the extent of the increase in high and low molecular weight (MW) organics was different for the effluents from SBRs operated at 8 and 20 °C. Results of SMP modelling demonstrated that a reduction in SBR operating HRT induced decreased utilization associated product (UAP) yields and the influence was greater at the SBR operating temperature of 8 °C. In contrast, biomass associated product (BAP) yields were relatively stable with SBR operating HRT but greater at lower SBR operating temperature. The effects of SBR operating HRT and temperature on fouling indices were also interactive. Reducing SBR operating HRT led to a lower increase in hydraulically reversible resistances and a greater increase in hydraulically irreversible resistances for the effluent from the SBR operated at 8 °C. Reducing the filtration temperature resulted in additional increase in membrane resistances, and the increase was greater at lower SBR operating HRT. The contribution of filtration temperature was observed to have the greatest impact on membrane resistances, followed in importance by SBR operating HRT and temperature. The comprehensive analysis undertaken in the present study provides insights into the interaction between secondary and tertiary operations on fouling development. The results can be employed to understand the limits of fouling control for tertiary treatment under challenging conditions.

New ultra high molecular weight acrylic processing aids for rigid PVC foaming

AbstractFoaming of rigid polyvinyl chloride (PVC) is studied as a function of high molecular weight acrylic processing aids. The industrial process to evaluate quality of foam is discussed in detail. The role of acrylic processing aids to improve melt strength and hence foaming of PVC is explained. It is demonstrated that increase in molecular weight of acrylic processing aids increases its effectiveness. It is found that ultra‐high molecular weight processing aids is 25%–30% more efficient than relatively lower, but still high, molecular weight acrylic processing aids. The higher molecular weight processing aids provided comparable foaming performance at lower loading levels. Foaming reduced the density of PVC compounds to 0.32–0.34 g/cm3. More than 1000% expansion is achieved in the melt extrusion process using a chemical blowing agent. Fusion characteristics are also studied. Fusion times for initial fusion peaks are in the range of 42–44 s while the fusion times of the second fusion peaks are in the range of 74–94 s. The higher molecular weight processing aids maintained fusion characteristics of PVC compounds, warranting no significant changes in commercial process.

Viscosity master curves and predictions of phenolic resin solutions through early aging

Dipping in solutions of phenolic resins is a common practice in obtaining various composite materials. One key control requirement is to identify the degree of aging of resin solutions in the dip tank, which would age inevitably through time. This work systemically studies the early aging of resin solutions, accompanied by the increase of molecular weights, viscosity, and glass transition temperature. Using rheological methods, this work formulates equations relating the viscosity, aging time, aging temperature, and measurement temperature, and provides a master surface. The aging time – aging temperature superposition is also validated. Based on the shifting factor, the unmeasurable slow aging around room temperature can now be predicted. During the early stage of aging, the glass transition temperature of the solution increases significantly. We propose a “viscosity-temperature index”, for instance, the ratio of viscosities at 0 and 30 °C. It can significantly reduce the error due to solution density, concentration, and viscosity measurement, and can be determined by a low-cost Brookfield-like viscometer near the production line. Combing the universal master curve of the viscosity-temperature index, now we can conveniently and precisely identify the aging degree of phenolic resin solutions.

Improvement of coagulating strength and toughness of alkoxysilanes for conservation of cultural heritage

AbstractThe optimal restoration agent for the brittle walls of Idout's tomb built 4400 years ago in Saqqara, Egypt, which is located underground in a desert area, was investigated. From x‐ray diffraction analysis of the sand collected near the tomb, the main ingredient is silica. Alkoxysilane and its oligomer are used because its alkoxy groups can react readily with silica. The compressive test of solidified model sand its main component is silica was done. The increase of both molecular weight of oligomer and the content of oligomer with higher molecular weight effectively developed the compressive force. When an earthquake occurs, it is desirable that the reinforced wall will be crushed in ductility. The addition of di‐alkoxy type alkoxysilane to oligomers changed the failure mode from brittle to ductile, because the network becomes looser. When a moderate quantity of di‐alkoxy type is added to oligomers, the solidified model sand deforms with greater displacement, while maintaining a high compressive force. From scanning electron microscopic observation of fractured solidified specimen, alkoxysilane was making the sand particles connect as a binder. Many cracks were clearly observed in the binder layer. Whereas, the formed crack was far smaller for di‐alkoxy added system.

Исследование гидродинамического влияния на молекулярные параметры продукта полимеризации изопрена в присутствии неодимсодержащего каталитического комплекса

The results of studying kinetic regularities in the process of obtaining polyisoprene in the presence of neodymium-containing catalytic systems for various technological modes of industrial production are presented. The process kinetic scheme is provided under conditions of the used catalyst monocenter, according to which a mathematical model of the process of isoprene polymerization for the process periodic and continuous modes is compiled. Kinetic approach to solving problems of chemical kinetics in combination with the method of moments was applied in the process mathematical description. To evaluate hydrodynamic influence exerted by the process implementation in a reactor cascade, the constructed kinetic model was supplemented with a macro-kinetic module that takes into account the relevant patterns. Features of the starting and static modes calculation in continuous production were determined. Numerical calculation methods were introduced to obtain dependences of alterations in the molecular parameters of the resulting product for a different number of reactors used in the continuous production system under static conditions. The hydrodynamic mode influence was shown in the reaction zone on the molecular weight distribution of the resulting product. As a result of computational experiments aimed at increasing the length of the reactor cascade, increase in the average molecular weights and approximation of the obtained values to the those characterizing the process periodic mode were noted

Preparation, physicochemical properties and antimicrobial activity of chitosan from fly pupae

As an alternative chitosan source, edible insects have been proposed as an unconventional but viable option. Taking fly pupae as an example, this work performed chitosan extraction through a traditional chemical method with some modifications, and investigated its physicochemical properties and antimicrobial activity. The results showed that adding 0.5% sodium sulfite (Na2SO3, w/w, Na2SO3/fly pupae) synergized with sodium hydroxide (NaOH) for deproteinization was more effective than lye alone. Acid leaching was applied for desalination, and the optimal concentration of hydrochloric acid (HCl) was determined as 2 mol/L by ash content. For decoloration, the optimal decolorization oxidant was sodium hypochlorite (NaClO) with a concentration of 1.0%. For the deacetylation of chitin to chitosan, both the yield and degree of deacetylation (DD) using segmented treatment with alkali-NaOH were higher than those of traditional one-time deacetylation. The established physicochemical properties corresponded with the typical characteristics of chitosan. The determination of antimicrobial activity of chitosan by the turbidimetric method showed that chitosan exhibited notable activity in the order of Staphylococcus aureus >Escherichia coli >Saccharomyces cerevisiae, and this effect decreased with the increase in viscosity-average molecular weight (Mη). These results proved the viability of our improved method for the preparation of chitosan, a valuable antimicrobial agent, using an alternative natural source.

Scalable manufacturing platform for the production of PEGylated heme albumin.

Cell-free heme, which was previously shown to have adverse effects on the innate immune system, does not induce inflammation when bound to a protein carrier via overexpression of the enzyme heme-oxygenase 1 (HO-1). Studies in mouse macrophage cell culture and human endothelial cells have confirmed HO-1 catalyzed breakdown of protein bound heme into biliverdin, iron, and carbon monoxide (CO), which elicits anti-inflammatory effects. However, to fully realize the anti-inflammatory therapeutic effects of heme, a colloidally stable heme protein carrier must be developed. To accomplish this goal, we incorporated multiple heme molecules into human serum albumin (HSA) via partial unfolding of HSA at basic pH followed by refolding at neutral pH, and subsequently conjugated the surface of the heme-HSA complex with polyethylene glycol (PEG) to stabilize heme-HSA. Quantification studies confirmed that a maximum of 5-6 hemes could be bound to HSA without precipitation or degradation of heme-HSA. Dynamic light scattering, size exclusion-high performance liquid chromatography (SEC-HPLC), and matrix-assisted laser desorption/ionization time-of-flight(MALDI-TOF) mass spectrometry confirmed the increase in hydrodynamic diameter and molecular weight (MW), respectively, upon PEGylation of heme-HSA. Furthermore, PEG-heme-HSA was stable upon exposure to different pH environments, freeze-thaw cycles, and storage at 4°C. Taken together, we devised a synthesis and purification platform for the production of PEGylated heme-incorporated HSA that can be used to test the potential anti-inflammatory effects of heme in vivo.

Extractive fermentation for the production and partitioning of lipase and citric acid by Yarrowia lipolytica

Extractive fermentation is an efficient downstream process to segregate the desired product in a fermentative process. Here, an integrated extractive fermentation process with an aqueous two-phase system (ATPS) was applied to evaluate the lipase and citric acid production by Yarrowia lipolytica. For this purpose, the influences of polyethylene glycol (PEG) molecular weights, different salts and different concentrations as well as the pH of the potassium phosphate buffer were studied. Citric acid preferentially migrated to the salt-rich phase, whereas lipase mostly partitioned to the PEG-rich phase. The PEG2000 (30 wt%) + salt (7 wt%) system provided higher cell growth and citric acid production, whereas the PEG2000/Na2SO4 ATPS showed a better recovery yield (79.75%) for citric acid. The increase in PEG molecular weight reduced lipase production and the partition coefficient (KL). In the PEG 2000/KH2PO4-K2HPO4 (pH 7) system, a lipase production of 634.32 U L−1 and KL = 2.22 was obtained. Lipase production kinetics in an Erlenmeyer (10 mL) and a bioreactor (1.5 L) demonstrated that in the ATPS, the fermentation medium caused a delay in the growth curve and a peak in lipase production, of which the latter allowed for a reduction in the dissolved oxygen concentration, limiting cell metabolism.

Influence of the Matrix Molecular Weight on the Morphology and Properties of Poly(Ethylene Terephthalate)/Poly(Ethylene-Octene) Blends

Poly(ethylene terephthalate)/poly(ethylene-octene) (PET/POE) blends compatibilized with glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) were prepared by melt blending using a twin screw extruder. The effects of the molecular weight of the PET matrix on the morphology and properties of the PET/POE/mPOE blends are described. The results of the SEM analysis showed that the average particle diameters of the dispersed phase decreased with an increase in the PET molecular weight. The results of the mechanical property tests showed that the notch Charpy impact strength and elongation at break of the PET/POE/mPOE blends improved with an increase in the PET molecular weight. However, the flexural strength, flexural moduli and tensile strength were nearly unchanged. The crystallization rate of PET in the PET/POE/mPOE blends improved with decreasing PET molecular weight.

Kevlar-like Aramid Polymers from Mixed PET Waste.

This work describes the synthetic approaches, spectroscopic and thermal characterization of aramid polymers prepared from waste polyethylene terephthalate (PET) via sustainable and scalable processes. Direct depolymerization of PET with aliphatic diamines under melt conditions resulted in decomposition without substantial formation of any aramid polymer. The Higashi–Ogata methodology or direct polycondensation of terephthalic acid (TPA) derived from PET waste and p-phenylenediamine, resulted in oligomerization and formation of aramids with a low degree of polymerization. The highest molecular weight polymers were obtained via the acid chloride of TPA, the traditional method. A proprietary solvent enabled the dissolution of most polymers and subsequent size exclusion chromatography analysis in the same solvent. We emphasize that although the soluble polymer compounds are prepared via the traditional route, they are novel. The apparent molecular weights of the soluble polymers ranged between 10–35 kDa (Mn) and 28–81 kDa (Mw). All analogues were prepared with commercially available diamines and diamine combinations. The obtained solid powders were dissolved in D2SO4 and analyzed spectroscopically to qualitatively evaluate the degrees of polymerization, while the solids were characterized via thermogravimetric analysis and differential scanning calorimetry. Many reaction conditions were employed to improve the solution polycondensation reaction, and it was found that addition of pyridine (2 eq) to the NMP reaction medium was crucial in preventing the precipitation of the polymer. Contrary to conventional wisdom, CaCl2 did not play a crucial role in the molecular weight increase of the polymer when oxydianiline was used. Our data indicated that the temperature and absence of CaCl2 provided a boost in molecular weight. Both room temperature and 0 °C reactions generated similar polymers as suggested by nuclear magnetic resonance; however, the cold conditions enhanced gel formation, an important attribute in the future processing of these materials to obtain fibers. All analogues had a high degradation temperature at 5 and 10% weight loss (5% and T10%), above 400 °C, along with high percent char values. A glass transition (Tg) was not detected in any of the analogues prepared.

Revisiting the multisite phosphorylation that produces the M-phase supershift of key mitotic regulators.

The term M-phase supershift denotes the phosphorylation-dependent substantial increase in the apparent molecular weight of numerous proteins of varied biological functions during M-phase induction. Although the M-phase supershift of multiple key mitotic regulators has been attributed to the multisite phosphorylation catalyzed by the Cdk1/cyclin B/Cks complex, this view is challenged by multiple lines of paradoxical observations. To solve this problem, we reconstituted the M-phase supershift of Xenopus Cdc25C, Myt1, Wee1A, APC3, and Greatwall in Xenopus egg extracts and characterized the supershift-producing phosphorylations. Our results demonstrate that their M-phase supershifts are each due to simultaneous phosphorylation of a considerable portion of S/T/Y residues in a long intrinsically disordered region that is enriched in both S/T residues and S/TP motifs. Although the major mitotic kinases in Xenopus egg extracts, Cdk1, MAPK, Plx1, and RSK2, are able to phosphorylate the five mitotic regulators, they are neither sufficient nor required to produce the M-phase supershift. Accordingly, inhibition of the four major mitotic kinase activities in Xenopus oocytes did not inhibit the M-phase supershift in okadaic acid-induced oocyte maturation. These findings indicate that the M-phase supershift is produced by a previously unrecognized category of mitotic phosphorylation that likely plays important roles in M-phase induction.