Non-phthalate plasticizer from camphor for flexible PVC with a wide range of available temperature

A bio-based plasticizer, (1′,7′,7′-trimethyldispiro [ [1,3]dioxolane-2,2′-bicyclo [2.2.1]heptane-3′,2″- [1,3]dioxolane]-4,4″-diyl)bis (methylene) dioctanoate (abbreviated as CDO), was designed to replace a traditional phthalate-based plasticizer. The structure of CDO was analyzed by ¹H NMR. The characteristics of CDO plasticizers, which were judged to have excellent compatibility with PVC due to their solubility parameters, were evaluated by thermal and mechanical analyses and compared with dioctylphthalate (DOP). PVC with 20% CDO added was thermally stable up to 251.9 °C and exhibited excellent strength and flexibility with a high T_g derived from its robust and bulky structure. In addition, since CDO is intertwined with the polymer chain, it shows excellent migration properties in many solvents. The results of our study suggest that CDO can be applied to produce flexible PVC and to expand PVC coverage due to the improved migration resistance.     

Dynamic mechanical behavior of the dioctyl phthalate plasticized polyvinyl chloride-epoxidized soya bean oil

The mixing of polyvinyl chloride (PVC) with dioctyl phthalate (DOP) shows two stages of gelation and fusion, but the homogeneity of each stage is influenced by the thermal stability of PVC and its rheological behavior. A torque rheometer has been used to gather almost all critical data related to the plasticized PVC in the epoxidized soya bean oil (ESBO). This study shows that, rheological data reflects the effects of DOP and epoxidization levels of SBO, in a DOP plasticized PVC-ESBO. The DOP plasticizer forms a thermodynamically miscible solution with ESBO; that reduces the rate of fusion and torque at balance of PVC. The storage modulus and tanδ of the plasticized PVC-ESBO have been used to show the extent of the homogeneity; but the dynamic mechanical behavior of PVC-ESBO is strongly influenced by DOP and the epoxidization level of SBO. The glass transition temperatures and dynamic properties of DOP plasticized PVC-ESBO are also reported and discussed in terms of the thermal stability and homogeneity of PVC.     

Viscoelastic and thermal characterization of crosslinked PVC

Soft PVC is employed for the manufacturing of a wide range of products with different properties and a relatively low cost. The utilization of soft PVC is restricted by the poor thermal, chemical and mechanical resistance properties. Also, plasticizer migration can modify the properties or can make useless the materials for some applications because of toxicity or a general loss of properties. PVC crosslinking is the most effective way to improve mechanical and transport properties of rigid or flexible PVC at high temperatures, but at the same time the thermal stability of PVC may be significantly reduced. In this work, the crosslinking reaction of plasticized poly(vinyl chloride) (PVC) through difunctional amines was studied. The mechanisms involved in the crosslinking reaction were explained by Fourier transform infrared (FTIR) analysis. The thermal activated crosslinking reaction was studied by cone and plate rheometry, analyzing the evolution of viscoelastic properties of the suspension as a function of time and temperature. The effect of the addition of crosslinking agents on the thermal stability of the polymer was studied by thermogravimetric analysis (TGA), which revealed that crosslinking reactions promote thermal degradation phenomena in the polymer matrix. This is attributed to the formation of HCl and other species promoting polymer degradation during crosslinking, thus leading to higher weight loss during thermal treatment with respect to unmodified PVC plastisols. This was also confirmed by an evident yellowing after crosslinking, especially at higher temperatures.     

Encapsulation of β-cyclodextrin by in situ polymerization with vinyl chloride leading to suppressing the migration of endocrine disrupting phthalate plasticizer

We performed the encapsulation of β-cyclodextrin (β-CD) in PVC by in situ polymerization with vinyl chloride monomer (VCM), and investigated the effect of CD encapsulation on the suppression of dioctyl phthalate (DOP) migration suspected as endocrine disruptor. β-CD was partially modified with 3-(methacryloxy)propyl trimethoxysilane and modified β-CD (MCD) was then encapsulated in PVC through suspension polymerization via radical reaction between double bonds MCD and VCM. Resulting MCD-encapsulated PVC (MCD_x-PVC) exhibited the similar morphology and characteristics to commercial PVC. For MCD_x-PVCs plasticized with DOP, they showed the considerably suppressed DOP migration as well as the similar optical and mechanical properties to conventionally plasticized PVC. In particular, the plasticized MCD_x-PVCs exhibited the superior suppression of DOP migration compared to the plasticized PVC where MCD and DOP were introduced by conventional melt mixing. Therefore, the encapsulation of MCD in PVC is thought to be an effective approach to producing the ecological PVC material.     

High-temperature pyrolysis of poly(vinyl chloride): Gas chromatographic-mass spectrometric analysis of the pyrolysis products from PVC resin and plastisols

A pyrolysis–gas chromatographic–mass spectrometric technique for analyzing the pyrolysis products from polymers in an inert atmosphere is described. Initial studies encompassing the pyrolysis of poly(vinyl chloride) homopolymer and a series of PVC plastisols (based on o-phthalate esters) have provided a complete qualitative and semi-quantitative analysis of the pyrolysis products from these materials. PVC resin yields a series of aliphatic and aromatic hydrocarbons when pyrolyzed at 600°C; the amount of aromatic products is greater than the amount of aliphatic products. Benzene is the major organic degradation product. A typical PVC plastisol [PVC/o-dioctyl phthalate (100/60)] yields, upon pyrolysis, products that are characteristic of both the PVC matrix and the phthalate plasticizer. The pyrolysis products from the plasticizer dilute those from the PVC portion of the plastisol and are, in turn, the major degradation products. There are no degradation products resulting from an interaction of the PVC with the plastisol. The pyrograms resulting from pyrolysis of the various plastisols of PVC can be used for purposes of “fingerprinting.” Identification of the major peaks in a typical plastisol pyrogram provides information leading to a precise identification of the plasticizer. The pyrolysis data from this study were related to a special case of flammability and toxicity.     

Synthesis of a bio-based plasticizer from oleic acid and its evaluation in PVC formulations

The bio-based plasticizers have been extensively developed due to their high compatibility and low toxicity. In this study, the bio-based plasticizers of methyl 10-(2-methoxy-2-oxoethansulfonyl) octadecanoate (MDA) and ethyl 10-(2-ethoxy-2-oxoethanesulfonyl) octadecanoate (EDA) were synthesized from the oleic acid and thioglycolic acid and characterized by ¹HNMR and FT-IR. The prepared materials were applied as plasticizers in Poly(vinyl chloride) (PVC) and their properties were compared with the commercial plasticizer, Bis(2-ethylhexyl) phthalate (DOP). The viscosities of prepared plastisols from novel designed plasticizers were lower than DOP. The results of mechanical properties showed that the synthesized plasticizers of MDA and EDA have the ability of plasticizing effects similar to DOP on PVC. Thermogravimetric analysis (TGA) indicated that both MDA and EDA have higher thermal stability than DOP. Two polar ester as well as polar sulfone groups in the chemical structure of MDA and EDA led to lower migration, volatility and exudation than DOP.     

Optimization of the curing conditions of PVC plastisols based on the use of an epoxidized fatty acid ester plasticizer

The use of an epoxidized fatty acid ester (EFAE) as a natural-based plasticizer for plasticized PVC (P-PVC) has been evaluated in this work. The effect of the curing conditions has been studied by following several test techniques such as mechanical properties, thermal behavior, color changes, solvent migration and microstructure. Different curing processes at isothermal conditions (ranging from 160 °C to 220 °C) have been carried at curing times in the 6–16 min range. The optimum mechanical response (tensile strength values in the 9–10 MPa range and elongation at break close to 250%) is obtained for plastisols cured at 200 and 220 °C for 12 and 8 min curing times, respectively. These curing conditions also offer the lowest migration in n-hexane (lower than 11%) which is indicative of plasticizer total absorption. Furthermore, the use of these curing conditions does not lead to thermal degradation as confirmed by color measurements.     

Effect of Plasticizer Type and Concentration on Dynamic Mechanical Properties of Sugar Palm Starch–Based Films

In the quest for biodegradable and environmentally friendly packaging materials, starch-based films have been considered as a potential alternative to address ecological problems that emerged from the use of nonbiodegradable petroleum-based plastics. Thus, this article presents a new biopolymer (sugar palm starch) for the preparation of biodegradable packaging films using the solution-casting technique. The effects of different plasticizer types (glycerol [G], sorbitol [S], and glycerol-sorbitol [GS] combination) with varying concentrations (0, 15, 30, and 45, w/w %) on the dynamic mechanical properties of sugar palm starch (SPS) films were evaluated. It was observed that the storage (E′) and loss modulus (E″) of the plasticized SPS films decrease as plasticizer concentration increases from 15 to 45%. S-plasticized films showed higher storage modulus (1000 MPa) than G (880 MPa) and GS (920 MPa) plasticized films, irrespective of plasticizer concentration.     

End-capped biobased saturated polyesters as effective plasticizers for PVC

In this work, flexible PVC formulations were prepared using biobased end-capped saturated polyesters (SPs). The SPs were end-capped for the first time with long alkyl chains (both branched (2-tetradecyloctadecan-1-ol, TDOD) and unbranched (octanol, Oc) aiming to increase the compatibility with PVC matrix, free volume and reduce migration. The properties of PVC samples plasticized with the SPs were compared with a PVC sample plasticized with dioctyl terephthalate (DOTP). A significant decrease in the T_g (60 °C <ΔT_g<80 °C) of PVC plasticized films was observed, and the samples plasticized with the SP end-capped with Oc presented an elongation at break (ε) value very close to the DOTP-plasticized PVC. Migration tests revealed that PVC plasticized with SPs have lower amount of extractables, especially those using Oc end-capped SP. Also, the decrease of thermomechanical properties of the samples plasticized using SPs is almost negligible when compared with the samples plasticized with DOTP. Overall, the results showed that the SP end-capped with Oc is a reliable alternative to DOTP.     

Sol-Gel Transition and Equilibrium Shear Modulus of Poly(vinyl chloride) and Plasticizers

The elasticity of poly(vinyl chloride) gels with molecular weight distribution (M_w/M_n), of 2.16 have been studied in the region beyond their gel points. Dynamic storage modulus G′, and equilibrium gel shear modulus of elasticity G_e, at low frequencies (ω) have specific developments as a function of polymer concentrations c, and plasticizers. The scaling elasticity from G_e = kε^z equation holds at different PVC plasticizer gels. The scaling exponent z, and constant k. ε is defined as the relative distance, ε = (|c − c_g|)/c_g, the calculated z = 2.45 ± 0.15. Furthermore, this analysis provides constant k with certain informations about the dependency of gel elasticity on the kind of plasticizer. Near the sol-gel transition temperature T, G_e decreases rapidly with increasing temperature. The normalized moduli G_eM/cRT, of the gels at different temperature, and/or c were dependent on the relative distance from the gelation point ε, and PVC and plasticizers concentration respectively. These results suggested mesh size of gel network near the gelation point for PVC with bis(2-ethylhexyl) phthalate (DOP) or di-n-butyl sebacate (DBS) plasticizers that has been newly reported.     

Free radical polymerization of glycidyl methacrylate in plasticized Poly(vinyl chloride)

Kinetic of free radical in-situ polymerization of glycidyl methacrylate (GMA), was studied in a complex evolutionary system: poly(vinyl chloride) (PVC) plastisols. A predictive model of conversion-time profile based on free radical mechanism was proposed and structure of the modified PVC system developed was investigated by NMR analyses. In order to elucidate the mechanism of the reaction, model molecules for PVC were used with NMR and MALDI-TOF characterization. It was found that in-situ polymerization of GMA in PVC plastisols leads to both homopolymerization and grafting of GMA onto PVC backbone by hydrogen abstraction. For 33 wt% GMA loaded, grafting efficiency is 67% with an amount of grafted poly-glycidyl methacrylate (pGMA) equals to 22 wt%. Thus, this article discloses a new type of PVC plastisols called reactive plastisols where, in addition to usual plasticizers, PVC is modified by polymerizable GMA monomer.     

细菌聚γ-谷氨酸溶液流变性能的研究

用分散聚合法制备了苯乙烯 甲基丙烯酸甲酯微米级单分散共聚物微球 ,粒径为 5 4 μm .将分散聚合体系与乳液聚合体系进行了比较 ,并对共聚物微球的形貌、粒径分布及共聚情况进行了表征研究     

GC-MS Assisted with Chemometric Methods Applied for Investigation of Migration Behavior of Phthalate Plasticizers in Fatty Foods Simulant

PVC films with different thickness and different contents of 9 phthalate plasticizers (PAEs) were manufactured according to a uniform design method. The migration contents of PAEs in isooctane, which was set as a fatty foods simulant, were first determined using GC-MS analysis. It was found that the chromatographic peaks of diisononyl ortho-phthalate (DINP) and diisodecyl ortho-phthalate (DIDP) very considerably overlapped, with a lower signal to noise ratio (SNR). For resolution of the noisy overlapped peaks, twice continuous wavelet transform (CWT) was adopted. Then, the migration models of PAEs were obtained by the non-negative least squares method (NNLS). The results show that the noisy overlapped peaks were successfully resolved with increasing the SNR 10 times; the migration ratio of the 9 PAEs at 70 °C are located with the range 0.0556–0.3383 %; the migration amount of a specific plasticizer is proportional to its content and some coexisting plasticizers; temperature is a significant impact factor for the migration process. The proposed chemometric-assisted GC-MS analysis provides a new approach for investigation of this complex process.     

Thermorheological analysis of PVC blends

The effect of temperature on dynamic viscoelastic measurements of miscible poly (vinyl chloride) (PVC)/ethylene‐vinyl acetate–carbon monoxide terpolymer (EVA‐CO) and immiscible PVC/high‐density polyethylene (HDPE) and PVC/chlorinated polyethylene (CPE) molten blends is discussed. PVC plasticized with di(2 ethyl hexyl) phthalate (PVC/DOP) and CaCO₃ filled HDPE (HDPE/CaCO₃) are also considered for comparison purposes. Thermorheological complexity is analyzed using two time–temperature superposition methods: double logarithmic plots of storage modulus, G′, vs. loss modulus, G″, and loss tangent, tan δ, vs. complex modulus, G*, plots. Both methods reveal that miscible PVC/EVA‐CO and PVC/DOP systems are thermorheologically complex, which is explained by the capacity of PVC to form microdomains or crystallites during mixing and following cooling of the blends. For immiscible PVC/HDPE and PVC/CPE blends the results of log G′ vs. log G″ show temperature independence. However, when tan δ vs. log G* plots are used, the immiscible blends are shown to be thermorheologically complex, indicating that the morphology observed by microscopy and constitued by a PVC phase dispersed in a HDPE or CPE matrix, is reflected by this rheological technique. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 469–477, 2000     

PVC/MMT nanocomposites

Poly(vinyl chloride) (PVC) nanocomposites with sodium montmorillonite (Na-MMT) and organically modified MMT (O-MMT) have been prepared by melt processing using mixing and extrusion techniques. The differential scanning calorimetry (DSC) with stochastic temperature modulation (TOPEM?) results show that the glass transition temperature (T _g) of PVC is slightly higher than T _g of PVC/Na-MMT and PVC/O-MMT which would indicate that MMT plays a role of an internal plasticizer that increases the distance between the PVC macrochains. The DSC TOPEM non-reversing heat flow profiles show enthalpy relaxation effects, and the lowest value has been found for pristine PVC—the presence of MMT (both Na+ and ammonium salt modified) may generate a certain orientation level of PVC macrochains during the extrusion process. Specific heat vs temperature dependencies at different frequencies revealed that the best fit to the single profile was found for PVC/Na-MMT nanocomposite, and this observation may be related to internal stability of the composite material as confirmed by analysis of the change in the specific heat (Δc _p).     

Effects of the degree of surface modification on the rheological responses of precipitated silica suspensions in benzyl alcohol

Two types of precipitated silica powders modified by poly (dimethylsiloxane) (PDMS) were suspended in benzyl alcohol and their rheological properties were investigated as a function of silica volume fraction, φ. The suspensions were classified into sol, pre-gel, and gel states based on the increase in φ. An increase in the degree of surface modification by PDMS caused gelation at higher φ. Plots of apparent shear viscosity against shear rate in the sol and pre-gel states of highly modified silica suspensions showed weak shear thickening behavior, while the same plots for silica suspensions with a low modification level exhibited shear thinning behavior. The dynamic moduli of hydrophobic suspensions in the pre-gel and gel states were dependent on the surface modification: the storage modulus G′ was larger than the loss modulus G″ in the linear region and these moduli increased with increasing φ, irrespective of the silica powder. The linear region of the φ range for the precipitated silica suspensions was wider than that for the fumed silica powders modified by PDMS suspended in benzyl alcohol, while the G′ value in the linear region for the precipitated silica suspensions was less than those for the fumed silica suspensions.     

旋转模塑过程中PVC溶胶物理凝胶化转变的有限元分析

采用有限元法,数值模拟了成型过程中镍制模具和PVC材料的非稳态温度场,进而得到了PVC材料结构参数的时间演变和空间分布规律,再由结构-性能关系获得了PVC材料的溶胶黏度及其演变特点,在此基础上比较分析了不同增塑剂对PVC材料物理凝胶化转变过程的影响.结果表明,由于热阻不同,靠近模具壁的PVC溶胶升温速率较大,首先发生凝胶化转变;加热过程中,PVC材料的黏度首先降低至最小值,凝胶化转变开始后,PVC树脂和增塑剂之间的相互作用增强,材料黏度迅速升高;不同增塑剂对材料结构参数和溶胶黏度的演变规律有着不同影响.     

不同分子量可德胶水悬浮液的粘弹性研究

采用动态粘弹性测量研究了不同分子量的生物大分子可德胶 (Curdlan)水悬浮液 (ASC)的流变学特性 .室温下观察到ASC具有弹性 (Solid like)行为 ,储能模量G′在测量范围内轻微依赖频率 ,而损耗模量G″和损耗角正切tanδ存在最小值 .ASC粘弹性随可德胶分子量和浓度的增加而增强 .ASC的流动特性符合Herschel Bulkley模型 ;其弹性行为可以通过渗流理论的标度弹性模型来描述 .网络结构是由于可德胶颗粒聚集或絮凝而形成的 ,当可德胶含量超过临界浓度cs=0 3 %时 ,弹性模量G′与可德胶浓度存在标度关系G′=Goεt,其中标度指数t=2 5 4.     

Effect of Solvent (Plasticizers) on PVC Degradation

Both plasticized (semi-rigid and flexible) PVC materials as well as PVC in solutions, the rate of their thermal degradation and effective stabilization are caused by essentially different fundamental phenomena in comparison to aging of PVC in absence of the solvent. Both structure and macromolecular dynamics render the significant influence on its stability, i.e. chemical nature of the solvent (plasticizer), its basicity, specific and non-specific solvation, degree of PVC in a solution (solubility), segmental mobility of macromolecules, thermodynamic properties of the solvent (plasticizer), formation of associates, aggregates, etc. The chemical stabilization of PVC plays a less significant role. The effect of above factors on stability (behavior) of semi-rigid and flexible PVC will be done on quantitative level. It will be described effect of “echo”-type of stabilization on the stability of PVC in the presence of plasticizers. If we would like to have stable material from PVC we should make stabilization of plasticizers as more reactive chemical compounds.     

Arabinoxylan networks as affected by ovalbumin content

Solutions (1% w/v) of water-extractable arabinoxylans (WEAX) from wheat were mixed with ovalbumin solutions at different concentrations in order to obtain different protein/polysaccharide ratios (0, 0.6, 2.5, 5.0, 7.5 and 10.0). These mixtures were oxidized by a laccase (Pycnoporus cinnabarinus). The kinetics of gelation was monitored by rheological measurements of the storage modulus (G′) and loss modulus (G″) at 25°C during 2 h. In the different ovalbumin/WEAX mixtures, WEAX cross-linking occurred as shown by an increase in G′. However, final G′ decreased as a function of protein concentration from 17.2 Pa (WEAX) to 7.1 Pa (ovalbumin/WEAX=10), following a sigmoidal relationship. Ovalbumin is probably entrapped in a WEAX covalent network, which explains the changes in rheological properties, but it does not participate in the network formation. Ferulic acid oxidation and diferulic acid formation was delayed at ovalbumin/WEAX=5.0 until 40 min but not at the end of gelation. In the same mixture SH groups from ovalbumin oxidized more rapidly than the protein alone. Ovalbumin via SH groups are probably responsible for the FA oxidation delay and the weaker WEAX gel formed by blocking the enzymatically formed free radicals.