Weight-average Molecular Mass Research Articles

Synthesis of new branched urethane-triazole polymers

An AB2 monomer obtained via the reaction of hexamethylene diisocyanate with 1,3-diazidopropan-2-ol and 2-propyn-1-ol contains one triple bond (A) and two azide groups (B2). Hyperbranched urethane-triazole polymers were synthesized through stepwise polymerization of this monomer via 1,3-dipolar cycloaddition. Owing to the presence of impurities of compounds with four azide groups (the products of the reaction of hexamethylene diisocyanate with two molecules of diazidopropanol) and two propyne groups (the product of the reaction of hexamethylene diisocyanate with two molecules of 2-propyne-1-ol) in the aforementioned monomer, uretane-triazole “polymers” are not classical huperbranched polymers, they are highly branched polymers that are soluble in aprotic polar solvents and have weight-average molecular masses of 5–260 and values of the exponent in the Kuhn-Mark-Houwink equation of 0.23–0.36.

Microstructure and Basic Properties of Domestic Butyl Rubber 1751

The characterization of microstructure and basic properties of domestic butyl rubber 1751 ( IIR 1751) was performed with different testing , such as 1H-NMR spectrum, gel permeation chromatography, dynamic mechanical analysis, thermal gravimetric analysis and differential scanning calorimeter. And the comparison with Butyl 268 and Butyl 301 was made. The results showed that IIR1751 had a narrower molecular mass distribution, lower number-average molecular mass and lower weight-average molecular mass. The unsaturation degree of IIR1751 was close to Butyl 268 and Butyl 301. Its thermal stability was higher than the other and its ash content and volatile matter content was lower. Its glass transition temperature was same to Butyl 268’s, which was slightly higher than the Butyl 301. Dispersion of carbon black in IIR1751 vulcanizates was poor, but IIR1751 vulcanizates had good processing property, had a longer scorch safety period and fast curing rate. Its fatigue performance was good and its mechanical properties can achieve a better balance.

Antioxidant and antitumor activities of β-glucan-rich exopolysaccharides with different molecular weight from Paenibacillus polymyxa JB115

β-Glucan isolated from cell wall of fungi not only has low purity and yield, but also causes adverse effects. Consequently, extracellular β-glucan produced by microorganisms is the focus of this study. β-Glucan-rich exopolysaccharides (G-EPSs) with different molecular weights from Paenibacillus polymyxa JB115 were prepared by ultrafiltration and spray-drying. The weight-average molecular masses of the G-EPSs, P-SD-1 (spray-dried G-EPSs powder prepared below 100 kDa) and P-SD-2 (spray-dried G-EPSs powder prepared above 100 kDa), were 7.084×104 and 9.235×105 g/mol, respectively. β-Glucan content was 47.38% in P-SD-1 and 73.12% in P-SD-2. The hydroxyl radical- and superoxide radicalscavenging activities of P-SD-2 at 1 mg/mL (39.45 and 87.34%, respectively) were higher than those of P-SD-1 (30.32 and 53.06%, respectively). Maximal nitric oxide (22.24±1.34 μM) was generated in the presence of P-SD-2 (1 mg/mL) and the antitumor activity of P-SD-2 was higher than P-SD-1 in four tumor cell lines (HeLa, Sarcoma 180, A549, and Hep3B cells). Thus, antioxidant and antitumor activities could be enhanced by regulating the molecular weight of G-EPSs. We anticipate that the food and medicinal use of G-EPSs will follow further characterization of this class of exopolysaccharides.

Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

The aim of this study was to incorporate an alpha-olefin (1-hexene or 1-dodecene) in a high cis polybutadiene chain, using a neodymium versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system. The influence of alpha-olefin on polymerization reaction and polymer characteristics, using different weight ratios of butadiene/α-olefin, was evaluated. The copolymers were characterized by SEC, FTIR, NMR, TGA and viscosimetric analysis. The thermal stability of the polymer tended to increase with incorporation of alpha-olefins, while its microstructure was not affected. The weight average molecular mass (Mw) tended to increase and the polymerization conversion tended to decrease with increasing alpha-olefins content. The copolymers showed a lower intrinsic viscosity than for the homopolymer. The results indicated that the alpha-olefins were incorporated in the polybutadiene chain.

Integration of biopolymer production with process water treatment at a sugar factory

The present investigation has focused on generating a surplus denitrifying biomass with high polyhydroxyalkanoate (PHA) producing potential while maintaining water treatment performance in biological nitrogen removal. The motivation for the study was to examine integration of PHA production into the water treatment and residuals management needs at the Suiker Unie sugar beet factory in Groningen, the Netherlands. At the factory, process waters are treated in nitrifying-denitrifying sequencing batch reactors (SBRs) to remove nitrogen found in condensate. Organic slippage (COD) in waters coming from beet washing is the substrate used for denitrification. The full-scale SBR was mimicked at laboratory scale. In two parallel laboratory scale SBRs, a mixed-culture biomass selection strategy of anoxic-feast and aerobic-famine was investigated using the condensate and wash water from Suiker Unie. One laboratory SBR was operated as conventional activated sludge with long solids retention time similar to the full-scale (SRT >16 days) while the other SBR was a hybrid biofilm-activated sludge (IFAS) process with short SRT (4-6 days) for the suspended solids. Both SBRs were found to produce biomass with augmented PHA production potential while sustaining process water treatment for carbon, nitrogen and phosphorus for the factory process waters. PHA producing potential in excess of 60 percent g-PHA/g-VSS was achieved with the lab scale surplus biomass. Surplus biomass of low (4-6 days) and high (>16 days) solids retention time yielded similar results in PHA accumulation potential. However, nitrification performance was found to be more robust for the IFAS SBR. Assessment of the SBR microbial ecology based on 16sDNA and selected PHA synthase genes at full-scale in comparison to biomass from the laboratory scale SBRs suggested that the full-scale process was enriched with a PHA storing microbial community. However, structure-function relationships based on RNA levels for the selected PHA synthases could not be established and, towards this ambition, it is speculated that a wider representation of PHA synthesases would need to be monitored. Additionally at the factory, beet tail press waters coming from the factory beet residuals management activities are available as a carbon source for PHA accumulation. At pilot scale, beet tail press waters were shown to provide a suitable carbon source for mixed culture PHA production in spite of otherwise being of relatively low organic strength (≤ 10 g-COD/L). A copolymer of 3-hydroxybutyrate with 3-hydroxyvalerate (PHBV with 15% HV on a molar basis) of high thermal stability and high weight average molecular mass (980 kDa) was produced from the beet tail press water. The mixed culture accumulation process sustained PHA storage with parallel biomass growth of PHA storing bacteria suggesting a strategy to further leverage the utilization of surplus functional biomass from biological treatment systems. Integration of PHA production into the existing factory water management by using surplus biomass from condensate water treatment and press waters from beet residuals processing was found to be a feasible strategy for biopolymer production.

Flow behavior, thixotropy and dynamical viscoelasticity of sodium alginate aqueous solutions

Understanding of the rheological behavior of sodium alginate (SA) is fundamental either to design optimized products or to ensure stable flows. Of the SA samples tested that characterized by a M/G ratio of 0.38 and a weight–average molecular mass (Mw) of 1.180 × 105 g/mol, steady–shear flow, thixotropy and dynamical viscoelasticity tests were carried out to characterize rheological behavior of G–rich SA aqueous solutions as influenced by concentration (1.0–3.0%, w/v) and temperature (5–35 °C). These measurements were carried out by using an Anton Paar–Physica MCR 301 Rheometer. It was found that, above a critical shear rate, all G–rich SA solutions (1.0–3.0%, w/v) exhibited non–Newtonian shear–thinning behavior and the flow curves could be well described by the Cross model. The temperature–dependent behavior of 2.5% (w/v) SA had higher correlation to the Cross model and the Arrhenius relationship, while the flow activation energy tended to decrease with the increase of shear rate. The upward–downward rheograms showed that all the systems evaluated in this paper had a hysteresis loop which indicating strong thixotropic behavior, the higher the SA concentration, the stronger the thixotropic behavior. The dynamical viscoelastic properties characterized by oscillatory frequency sweep under small–deformation conditions showed a fluid–like viscoelastic behavior. The behavior of SA aqueous solutions was predominantly more viscous than elastic. Multiwave temperature ramp test for 2.5% SA aqueous solutions was consistent with the results from oscillatory frequency sweep test.

Efficient extraction and characterization of polymeric hemicelluloses from hybrid poplar

Hemicelluloses were isolated from hybrid poplar with the single-step alkaline extraction. Neutralization and subsequent ethanol precipitation were used to recover them. Their structures were investigated using sugar analysis, Fourier transform infrared and 13C nuclear magnetic resonance spectroscopy. The hemicelluloses were characterized by particle size analyzer, gel permeation chromatography and thermogravimetric analyzer. 36.4% and 50.4% of the original hemicelluloses were isolated in the form of polymer by neutralization and precipitation, respectively. The hemicellulosic fraction (HA) by neutralization was more homogeneous in sugar components than the one (HB) by precipitation. However, hemicellulose isolated by both of the process has chemical structure, as were (4-O-methylglucurono)-d-xylans. The weight average molecular mass of HA was 17,480gmol−1, higher than one of HB (14,670gmol−1) and they were both with a low polydispersity. HA had lower zeta potential and higher thermal stability than HB. Therefore, the procedures in this study were efficient for the isolation and the recovery of polymeric hemicelluloses with different properties.

Structure and molar mass analysis of pneumococcal capsular polysaccharides by 1H NMR and HPSEC-MALLS

Objective To analyze the structures and molecular weight distributions of the capsular polysaccharides from 6 serotypes of pneumococcus .Methods The structures of pneumococcal capsular pol-ysaccharides of 6 serotypes were analyzed by 1 H nuclear magnetic resonance （ NMR） .Chemical shifts of all characteristic protons were investigated to analyze polysaccharide integrity and inter -assay consistency .High performance size exclusion chromatography-multi angle laser light scattering （ HPSEC-MALLS） was used to measure the molecular weights .Results The chemical shifts of all characteristic protons of the pneumococ-cal capsular polysaccharides of 6 serotypes were consistent with the standard chemical shift .The weight-aver-age molecular mass of the pneumococcal capsular polysaccharides ranged from 7.182×104 g/mol（for serotype 19A） to 1.273×106 g/mol（for serotype 9V）examined by HPSEC-MALLS.Conclusion The structures and molecular weight distributions of pneumococcal capsular polysaccharides could be rapidly and effectively ana -lyzed by 1 H NMR and HPSEC-MALLS.Moreover, C-PS and acetate contained in capsular polysaccharides could also be detected .HPSEC-MALLS is an applicable method for the quantitative analysis of molar mass distributions in different serotypes of pneumococcal capsular polysaccharides . Although 1 H NMR and HPSEC-MALLS have been accepted as the quality control measurements by WHO , to use them as the re-placements of the traditional QC method still needs further investigation . Key words: Pneumococcal capsular polysaccharide; 1 H NMR; Chemical structure; HPSEC-MALLS; Weight-average molecular mass

MALDI-TOF Analysis of Polyhexamethylene Guanidine (PHMG) Oligomers Used as a Commercial Antibacterial Humidifier Disinfectant

Polyhexamethylene guanidine (PHMG) polymers used as an active ingredient in an antibacterial humidifier disinfectant were reported to cause harm to the human health when inhaled, although physical contact with this material was known to present low toxicity to humans. It is therefore necessary to develop an optimal analysis method which enables detection and analysis of PHMG polymers. MALDI-TOF investigations of PHMG are performed with a variety of matrices, and it is found that CHCA and 2,5-DHB are excellent matrices which well reflects the polymer population even at high mass. For the provided PHMG sample, the number-average (Mn) and weight-average (Mw) molecular masses were determined to be 744.8 and 810.7, respectively, when the CHCA was used as a matrix. The rank of the matrices in terms of averaged molecular weight was CHCA ~2,5-DHB > 5-NSA > DHAP, THAP > ATT > IAA ~ super-DHB ~ HABA. In addition, PSD of the PHMG oligomer ions exhibited a few unique fragmenation characteristics. The formation of a- and c-type fragments was the major fragmentation pathway, and the 25-Da loss peaks generally accompanied a- and c-type fragments.

Influence of chemical structure and chain length on conducting properties of dielectric polymers in metal/polymer/metal structures

The influence of weight-average molecular mass Mw on the maximal width of a conducting layer hmax of polysterene, polymethylmethacrylate, and polyamidine films was investigated. It was shown that hmax increases in proportion to MwS for all investigated polymers. It points to the fact that the hmax value is defined by the macromolecular coil size.

Blend polyolefin elastomers based on a stereoblock elastomeric PP

The principles of the creation of new blend polyolefin elastomers with a controlled complex of properties based on a stereoblock elastomeric PP synthesized in the presence of asymmetric ansa-metallocenes are proposed. Original blend polymer materials with reduced hardness that are based on elastomeric PPs with different characteristics and a 50–70 wt % oil-extended ternary ethylene-propylene-diene elastomer were prepared through the method of dynamic vulcanization. The molecular-mass characteristics of PP have a considerable effect on the rheological properties of polyolefin elastomers. For successful processing of the resulting blends, the pristine component, the elastomeric PP, must have a weight-average molecular mass of M w = (8−14) × 104 and a low crystallinity.

Study on preparation and self-assembly properties of hydrophobically associating polyacrylamide by emulsifier-free ultrasonic assisted radical polymerization

Through ultrasonic assisted radical polymerization, hydrophobically associating polyacrylamide (U-HAPAM) was prepared by acrylamide (AM), 2-acrylamido -2- methyl propane sulfonic acid (AMPS), and long-aliphatic-chain hydrophobic monomer octadecyl acrylate (ODA). The effects of ultrasonic frequency power on total monomer conversion, relative molecular mass and the aqueous solution behavior were discussed. The results showed that, when the ultrasonic power was 120 W, there was a good thickening ability, total monomer conversion was 76.36 %, relative weight-average molecular mass was 72500, the critical association mass concentration (C*) was 0.27 wt% and there were good intermolecular hydrophobically associating interactions in the copolymer aqueous solution. U-HAPAM was pseudoplastic fluid; the associating behavior of the U-HAPAM had apparent effects on the dynamic moduli (G′and G″) and the apparent average aggregate size (d*). When mass concentration of copolymer (Cm) was 0.40 wt%, the apparent viscosity attained 453.6 mPa·s. The viscosity retention index (VRI) was 60.99 % as the temperature reached 80 °C. The apparent viscosity of U-HAPAM in mineralized water was increased towards 502.9 mPa·s as the degree of mineralization (M) was 19334 mg/L. Under the effect of ultrasounds, the ODA was effectively introduced into U-HAPAM without micromolecule emulsifier, which endowed the copolymer good solution properties.

Estudo Viscosimétrico de Copolímeros à Base de 1,3-Butadieno e 1-Octeno em Tulueno e Hexano

Viscosimetry is a simple, inexpensive characterization method that provides valuable information about the hydrodynamic volume and conformation of macromolecules in solution, in a solvent, at a given temperature. The viscosimetric parameters can be mathematically calculated by graphic extrapolation, in time-consuming experimental tests. It is possible, however, to achieve results by a single point determination. In this work we used the two calculation methods employing a series of six equations: Huggins, Kraemer and Schulz-Blaschke, by graphic extrapolation; and Schulz-Blaschke, Solomon-Ciuta and Deb-Chanterjee, by a single point determination, for solutions of polybutadiene and of random copolymers of 1,3-butadiene and 1-octene, with different mass ratios (Bd/Oct = 99/1 and 97/3). The viscosimetric determinations were carried out in toluene and hexane, at 30 ± 0.1 °C. The weight average molecular mass was determined by size exclusion chromatography (SEC). The values of intrinsic viscosity and of some constants indicated that both toluene and hexane were good solvents for the samples, with hexane being better owing to the higher intrinsic viscosities when compared to the former. It was also observed that the method of calculation by a single point was valid. By means of the intrinsic viscosity values and the parameter g' (ratio between the viscosities of branched and linear polymer) the occurrence of branching in the copolymer chain was suggested because g'<1 and the values of intrinsic viscosity were lower than those obtained for the homopolymer.

Chemical Characterization and Structure of Exopolysaccharides from Submerged Culture of New Medicinal Mushroom from China, Phellinus mori (Higher Basidiomycetes)

Two different exopolysaccharides (EPSs) were first time-fractionated from submerged mycelia culture of Phellinus mori (PM) by gel-filtration chromatography: PM-EPS1 and PM-EPS3. Results of compositional analysis using high-performance anion exchange chromatography indicated that both PM-EPS1 and PM-EPS3 were heteropolysaccharides consisting of mannose, glucose, galactose, and rhamnose. Gel permeation chromatography analysis showed that the weight-average molecular mass of PM-EPS1 and PM-EPS3 were 4,990 g/mol and 27,890 g/mol, respectively. Fourier transform infrared spectral analysis of PM-EPS1 and PM-ESP3 revealed prominent characteristic groups corresponding to carbohydrates. 1H and 13C nuclear magnetic resonance spectroscopy analysis indicated that PM-EPS3 had a (1→4)-linked mannopyranosyl backbone, with branches of (1→4)-linked glucosyl residues and (1→3, 4)-linked galactopyranosyl residues. Preliminary activity tests in vitro revealed that the hydroxyl radical scavenging activity and total superoxide dismutase activities of PM-EPS3 obviously increased with an increase in concentration at the range 0.1-2.5 mg/mL.

Bimodal architecture and rheological and foaming properties for gamma-irradiated long-chain branched polylactides

A series of long-chain branched polylactides (LCB-PLAs) were prepared from a linear PLA precursor by applying gamma radiation with addition of the trifunctional monomer, trimethylolpropane triacrylate (TMPTA) and their topological structures were investigated by size-exclusion chromatography coupled with a multiangle light scattering detector (SEC-MALLS) and rheology. SEC-MALLS measurements show that LCB-PLAs exhibit not only the increased weight-average molecular mass but also a bimodal architecture with a short linear chain fraction and a LCB fraction, as compared with LCB-PLA samples generated by electron-beam radiation, which only show the monomodal macromolecular structure. The introduction of LCB structure contributes to the enhancement of complex viscosity, shear-thinning and storage modulus, and the deviations of phase angle, δ from the “universal” curve of linear PLA in δ(|G*|) plots (van Gurp–Palmen plot). By the analysis of the thermorheological behaviors and determination of activation energies, the bimodal architecture is confirmed. Activation energies around 77 kJ mol−1 lead to an expectation that some linear macromolecules are still present in LCB-PLAs, while the higher activation energies at large phase angles are associated with the existence of the LCB ones. A conclusion with respect to the tree-like topography for LCB-PLAs is drawn from the molecular mass dependences of zero-shear viscosity (η0–Mw plot). An explanation to these findings is provided under the consideration of the radiation dose rate for the gamma radiation. The remarkable modification of PLA topological chain structure contributes to the improvement of the foaming properties of LCB-PLAs.

Nano-structure of octenyl succinic anhydride modified starch micelle

The micelle nano-structures of octenyl succinic anhydride (OSA-starch) modified starches with different Mw (weight average molecular mass) in aqueous solution were studied. The micelle aggregates observation, maximum dimension (rmax) calculated from Pair Distance Distribution Function p(r) using General Indirect Fourier Transformation (GIFT) and radius of gyration (Rg) obtained from Guinier fitting of the small angle X-ray scattering data indicated the obvious geometric disparity of micelles originated from different OSA-starches. The micelle presented increased monodispersity in more concentrated aqueous solution. The OSA-starch molecules with the highest Mw formed the largest micelle. Hydrodynamic radius (Rh) via dynamic light scattering of the micelle with the highest Mw decreased in larger extent (from 80 nm to 46 nm), as well as more distinct change of Rg/Rh with increasing concentration, from which it could be deduced that the micelle conformation with higher Mw was more flexible and more sensitive to the interparticle electrostatic repulsion. Moreover, the most compact interior structure formed within the micelle with the highest Mw. The p(r) plots show typical profiles yielded from some oblate ellipsoid with a small subunit, long rod with a limited cross-section dimension and flattened prolate ellipsoid. It is anticipated that these nano-structures differences could be close related to stability and other properties of OSA-starch applied in oil-in-water system.

Method for chromatographic analysis of whey protein–dextran glycation products

A chromatographic method for the analysis of whey protein isolate (WPI)–dextran glycates was developed in this work that is useful for quantification of sample purity and concentration, and as a sample-preparation method for subsequent analysis by gel electrophoresis (SDS-PAGE) and laser-light scattering. Glycation was by the Maillard reaction between WPI and dextran of 3 different sizes. Glycate fractions from each dextran were collected and analyzed by fluorescent and glycoprotein staining of gels, bicinchoinic acid protein assay, and static and dynamic laser light scattering. The weight-average molecular mass of the glycates was 27–34kDa (from 3.5kDa dextran), 32–39kDa (from 10kDa dextran), and 250–270kDa (from 150kDa dextran). The new method was used to characterize the kinetics of the glycation reaction, which followed a reversible pseudo first-order model. The kinetics of decomposition of the purified glycate by hydrolysis was also examined. The new method is rapid (25min) and quantitative, and is the first chromatographic method for direct analysis of WPI-dextran glycation products.

Characterization of the Molecular Architecture of Human Caveolin-3 and Interaction with the Skeletal Muscle Ryanodine Receptor

Caveolin-3 facilitates both caveolae formation and a range of cell signaling pathways, including Ca(2+) homeostasis. Caveolin-3 forms a disc-shaped nonamer that binds the Ca(2+)-release channel, RyR1. Multiple caveolin-3 nonamers bind to a single RyR1 homotetramer. First three-dimensional structural insights into caveolin-3 assembly, interactions with RyR1 suggest a novel role in muscle contraction and/or for channel localization within the membrane. Caveolin-3 (cav-3), an integral membrane protein, is a building block of caveolae as well as a regulator of a number of physiological processes by facilitating the formation of multiprotein signaling complexes. We report that the expression of cav-3 in insect (Sf9) cells induces caveola formation, comparable in size with those observed in native tissue. We have also purified the recombinant cav-3 determining that it forms an oligomer of ∼220 kDa. We present the first three-dimensional structure for cav-3 (using transmission electron microscopy and single particle analysis methods) and show that nine cav-3 monomers assemble to form a complex that is toroidal in shape, ~16.5 nm in diameter and ~ 5.5 nm in height. Labeling experiments and reconstitution of the purified cav-3 into liposomes have allowed a proposal for the orientation of the protein with respect to the membrane. We have identified multiple caveolin-binding motifs within the ryanodine receptor (RyR1) sequence employing a bioinformatic analysis. We have then shown experimentally that there is a direct interaction between recombinant cav-3 nonamers and purified RyR1 homotetramers that would imply that at least one of the predicted cav-3-binding sites is exposed within the fully assembled RyR1 structure. The cav-3 three-dimensional model provides new insights as to how a cav-3 oligomer can bind multiple partners in close proximity to form signaling complexes. Furthermore, a direct interaction with RyR1 suggests a possible role for cav-3 as a modifier of muscle excitation-contraction coupling and/or for localization of the receptor to regions of the sarcoplasmic reticulum.

Effects of degree of carboxymethylation on physicochemical and biological properties of pachyman

Polysaccharides (pachyman) extracted from Poria cocos sclerotium were chemically modified by carboxymethylation and the effects on the structural and biological properties of the polysaccharides were investigated as a function of the degree of carboxymethylation. The degree of substitution (DS) of five carboxymethylated pachyman, coded as CMP1/CMP2/CMP3/CMP4/CMP5, was determined to be 0.44–0.88. The structures were confirmed by FT-IR and their weight-average molecular masses (Mw) were obtained by SEC-LLS. Experimental results showed that derivatives were effective in anti-oxidation and bile acid binding in a dose dependent way. Furthermore, their water solubility and biological activities were improved with the increase of DS. Therefore, results proved that the carboxymethylation of pachyman effectively enhanced their potential biological properties.

Down-Regulation of Small Rubber Particle Protein Expression Affects Integrity of Rubber Particles and Rubber Content in Taraxacum brevicorniculatum

The biosynthesis of rubber is thought to take place on the surface of rubber particles in laticifers, highly specialized cells that are present in more than 40 plant families. The small rubber particle protein (SRPP) has been supposed to be involved in rubber biosynthesis, and recently five SRPPs (TbSRPP1–5) were identified in the rubber-producing dandelion species Taraxacum brevicorniculatum. Here, we demonstrate by immunogold labeling that TbSRPPs are localized to rubber particles, and that rubber particles mainly consist of TbSRPP3, 4 and 5 as shown by high-resolution two-dimensional gel electrophoresis and mass spectrometric analysis. We also carried out an RNA-interference approach in transgenic plants to address the function of TbSRPPs in rubber biosynthesis as well as rubber particle morphology and stability. TbSRPP-RNAi transgenic T. brevicorniculatum plants showed a 40–50% reduction in the dry rubber content, but neither the rubber weight average molecular mass nor the polydispersity of the rubber were affected. Although no phenotypical differences to wild-type particles could be observed in vivo, rubber particles from the TbSRPP-RNAi transgenic lines were less stable and tend to rapidly aggregate in expelling latex after wounding of laticifers. Our results prove that TbSRPPs are very crucial for rubber production in T. brevicorniculatum, probably by contributing to a most favourable and stable rubber particle architecture for efficient rubber biosynthesis and eventually storage.