Improvement of polyamide/thermoplastic polyurethane blends with polyamide 6-polyurethane copolymer prepared via suspension polymerization as compatibilizer

The polyamide 6-polyurethane copolymer (PA6-b-PU-b-PA6) was synthesized through anionic suspension polymerization and then mixed with polyamide 6/thermoplastic polyurethane (PA6/TPU) and polyamide 6, 6/thermoplastic polyurethane (PA66/TPU) blends using as the compatibilizer. The results show that the PA6-b-PU-b-PA6 copolymers powders several can be obtained through suspension polymerization using dimethicone as disperse medium. The average diameter of PA6-b-PU-b-PA6 copolymer powders decreased with the increasing of PU content. With the addition of PA6-b-PU-b-PA6, the TPU phase dispersed more uniformly in PA6 or PA66 matrix, and the size of TPU dispersed phase decreased obviously. The PA6-b-PU-b-PA6 copolymer with higher PU content shows better compatibilizing effect. Addition of PA6-b-PU-b-PA6 can improve both strength and toughness of the PA/TPU blends. When the amount of PA6-PU25% copolymer was 5 phr, the tensile strength and notched impact strength of PA6/TPU/PA6-PU25% blends increased 29 and 159.4%, respectively, compared to the PA6/TPU blend without compatibilizer.     

Triple-shape memory properties of thermoplastic polyurethane/olefin block copolymer/polycaprolactone blends

Thermoplastic polyurethane (TPU)/olefin block copolymer (OBC)/polycaprolactone (PCL) blends (70/20/10 and 50/30/20) were melt-blended to form the first environmental OBC-based triple-shape memory polymer blends. In this work, PCL with low crystalline temperature (switching phase), OBC with medium crystalline temperature (switching phase), and TPU with high crystalline temperature (fixed phase) could form an alternative triple-shape memory polymer (TSMP). Two compatibilizers, OBC-g-glycidyl methacrylate (OBC-g-GMA) and dicumyl peroxide, were confirmed to show a synergistic effect in enhancing the compatibility further through the morphological observation. Crystallinity of both OBC and PCL in the blends with or without modification decreased in comparison with that of pure resin. For dual-shape behaviors, the shape fixing ratio (R_f) and shape recovery ratio (R_r) were up to 96.3% and 91.2% for the GMA and peroxide-modified blends (50/30/20). The higher amount of TPU didn’t give higher recovery ratio, but instead slightly lower R_r due to the morphology difference. For triple-shape behaviors, both TPU/OBC/PCL blend compositions with or without GMA or peroxide modifications gave high R_f(C→B) values in the first fixing stage, but slightly lower values R_f(B→A) in the second fixing stage, especially for (70/20/10) case. On the other hand, a reverse trend was observed for two recovery stages. To enhance the R_f(B→A) in the second fixing stage, higher deformation temperatures were considered, and a measurable increment on R_f(B→A) was attained. Through this subtle adjustment on the temperature difference between high and low deformation temperatures, the theoretical multi-shape memory shape could be readily tailored to meet different applications.     

Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer

To prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH₂ provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Relationship between branch length and the compatibilizing effect of polypropylene‐g‐polystyrene graft copolymer on polypropylene/polystyrene blends

Three polypropylene‐g‐polystyrene (PP‐g‐PS) graft copolymers with the same branch density but different branch lengths were evaluated as compatibilizing agents for PP/PS blends. The morphological and rheological results revealed that the addition of PP‐g‐PS graft copolymers significantly reduced the PS particle size and enhanced the interfacial adhesion between PP and PS phases. Furthermore, it is verified that the branch length of PP‐g‐PS graft copolymer had opposite effects on its compatibilizing effect: on one hand, increasing the branch length could improve the compatibilizing effect of graft copolymer on PP/PS blends, demonstrated by the reduction of PS particle size and the enhancement of interfacial adhesion; on the other hand, increasing the branch length would increase the melt viscosity of PP‐g‐PS graft copolymer, which prevented it from migrating effectively to the interface of blend components. Additionally, the crystallization and melting behaviors of PP and PP/PS blends were compared. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40126.     

Preparation and characterization of two-way shape memory olefin block copolymer/silicone elastomeric blends

Very few olefin block copolymer (OBC)-based shape memory polymers (SMPs) studies were reported in the literature so far. This study investigated the preparation of OBC and silicone elastomeric blends (70/30 and 50/50) using a melt-blending technique to form the first two-way OBC-based SMPs, to our best knowledge. Two phr of ((2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (DHBP) was used to prepare flexible OBC/silicone D2 (D2 representing 2 phr of DHBP) networks. DHBP not only assisted the curing of OBC and silicone but also increased their compatibility in the blends. Despite the very low crystallinity of the OBC elastomer component, 10.4%, corresponding to only ~7% based on total resins in the OBC/silicone D2 70/30 blend, the rare two-way shape memory behavior at such a low crystallinity was still envisaged. Regarding two-way shape memory results at various loads, both entropy-driven and crystallization-driven contributions to the overall actuation magnitude (R_act) were at the highest level under 450 kPa, attributing to the highest orientation of molecular networks in the blends. With increasing the applied stress, the R_act of OBC/silicone (70/30) sample increased from 4.1% to 23.7% due to the increased strain-induced crystallization effect confirmed by the XRD (X-ray diffraction) evaluation, while the recovery magnitude (R_rec) was maintained at the high level, close to 90%, without the hindrance of high load on the recovery due to high elasticity of silicone rubber. Besides, the crystallization-driven contribution to the overall actuation magnitude was higher for the blends containing the higher amount of crystalline OBC elastomer in the blends. On behalf of silicone with outstanding thermal stability, high elastic behavior, and high hydrophobicity, OBC/silicone SMP blends with versatile properties could meet different applications.     

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

The compatibilizing effect of the triblock copolymer poly(styrene-b-butadiene-b-styrene) (SBS) on the morphology and mechanical properties of immiscible polypropylene/polystyrene (PP/PS) blends were studied. Blends with three different weight ratios of PP and PS were prepared and three different concentrations of SBS were used for investigations of its compatibilizing effects. Scanning electron microscopy (SEM) showed that SBS reduced the diameter of the PS-dispersed particles as well as improved the adhesion between the matrix and the dispersed phase. Transmission electron microscopy (TEM) revealed that in the PP matrix dispersed particles were complex “honeycomblike” aggregates of PS particles enveloped and joined together with the SBS compatibilizer. Wide-angle X-ray diffraction (WAXD) analysis showed that the degree of crystallinity of PP/PS/SBS slightly exceeded the values given by the addition rule. At the same time, addition of SBS to pure PP and to PP/PS blends changed the orientation parameters A₁₁₀ and C significantly, indicating an obvious SBS influence on the crystallization process in the PP matrix. SBS interactions with PP and PS influenced the mechanical properties of the compatibilized PP/PS/SBS blends. Addition of SBS decreased the yield stress and the Young's modulus and improved the elongation at yield as well as the notched impact strength in comparison to the binary PP/PS blends. Some theoretical models for the determination of the Young's modulus of binary PP/PS blends were used for comparison with the experimental results. The experimental line was closest to the series model line. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 2625–2639, 1998     

氟橡胶接枝马来酸酐增容氟橡胶/热塑性聚氨酯共混物的性能

研究了氟橡胶(FKM)接枝马来酸酐(FKM-g-MAH)增容FKM/热塑性聚氨酯(TPU)共混物的物理机械性能及动态力学性能.结果表明,当FKM-g-MAH质量分数为15%时,FKM/TPU共混物的物理机械性能最佳;添加增容剂FKM-g-MAH后,FKM/TPU共混物中FKM和TPU两相的相容性得到改善,且其阻尼性能优于纯FKM.     

热塑性聚氨酯弹性体与乙华平橡胶共混物的性能

将聚酯型和聚醚型聚氨酯弹性体(TPU385E,TPU8685)分别与不同乙酸乙烯酯含量的乙华平橡胶(EVM400,EVM700)进行共混,考察了原料种类、共混比对共混物力学性能和耐磨性的影响。结果表明,随着TPU用量的增加,EVM/TPU共混物的拉伸强度、邵尔A硬度、100%定伸应力和300%定伸应力均提高,扯断伸长率下降;随着EVM用量的增加,EVM/TPU共混物的拉伸强度、邵尔A硬度、100%定伸应力和300%定伸应力均降低,扯断伸长率增大;随着TPU用量的增加,EVM/TPU共混物的耐磨性提高;TPU8685/EVM400共混物具有最大的拉伸强度,TPU385E/EVM700共混物具有最大的扯断伸长率,TPU8685/EVM700共混物具有最好的耐磨性;当2种TPU与EVM400质量比都为50/50时,TPU385E/EVM400的耐磨性最差。     

Properties of acrylonitrile–butadiene–styrene/polycarbonate blends with styrene–butadiene–styrene block copolymer

The importance of alloys and blends has increased gradually in the polymer industry so that the plastics industry has moved toward complex systems. The main reasons for making polymer blends are the strengthening and the economic aspects of the resultant product. In this study, I attempted to improve compatibility in a polymer blend composed of two normally incompatible constituents, namely, acrylonitrile–butadiene–styrene (ABS) and polycarbonate (PC), through the addition of a compatibilizer. The compatibilizing agent, styrene–butadiene–styrene block copolymer (SBS), was added to the polymer blend in ratios of 1, 5, and 10% with a twin‐screw extruder. The morphology and the compatibility of the mixtures were examined by scanning electron microscopy and differential scanning calorimetry. Further, all three blends of ABS/PC/SBS were subjected to examination to obtain their yield and tensile strengths, elasticity modulus, percentage elongation, Izod impact strength, hardness, heat deflection temperature, Vicat softening point, and melt flow index. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2521–2527, 2004     

Evaluation of olefinic block copolymer blends with amorphous polyolefins—effect of different unsaturated and saturated hydrocarbon tackifier resins on blend miscibility

Blends of ethylene–octene based olefinic block copolymer (OBC) with two amorphous polyolefin (APO) polymers [atactic propylene homopolymer (PP) and ethylene–propylene copolymer (PE–PP)] were evaluated at three different ratios. Dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM) evaluations were performed to determine the blend miscibility characteristics. Viscoelastic properties of both OBC blends with PP polymer, and OBC blends with PE–PP copolymer showed incompatibility. Analysis revealed that both blends formed two phase morphologies. The effect of three unsaturated aliphatic hydrocarbon resins with varying aromatic content and two saturated hydrocarbon resins with different chemistries were evaluated as compatibilizing agent for OBC/PP and OBC/PE–PP blends. A 1 : 1 polymer blend ratio of OBC/PP and OBC/PE–PP was selected to better understand the influence of resin addition at three different levels 20, 30, and 40 wt %. The fully aliphatic unsaturated resin seems to improve the miscibility of the OBC/PP blends at higher resin addition levels, but reduced the miscibility as the aromatic content of the resin increases. However, OBC/PE–PP blends showed improved miscibility with increasing aromatic content. A ternary phase morphology was particularly observed for both OBC/PP and OBC/PE–PP blends with highly aromatic (14%) unsaturated hydrocarbon resin, in which OBC formed the continuous phase, and PP, PE–PP, and unsaturated hydrocarbon resins formed the dispersed phase. Interestingly, we did not observe much difference in miscibility characteristics between the two saturated resin chemistries in both blend systems (OBC/PP and OBC/PE–PP). The Harkins spreading coefficient concept was used to better understand the ternary blend dispersed phase morphology. Spreading coefficients indicate that the free hydrocarbon resins (both unsaturated and saturated) were encapsulated by the amorphous PP or amorphous PE–PP polymer in the dispersed phase for the respective blend compositions. Overall OBC–PP and OBC/PE–PP blends showed better miscibility characteristics with both saturated aliphatic hydrocarbon resins, irrespective of the difference in resin chemistries. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2624–2644, 2013     

Compatibilization effects of styrenic/rubber block copolymers in polypropylene/polystyrene blends

Compatibilizing effects of styrene/rubber block copolymers poly(styrene‐b‐butadiene‐b‐styrene) (SBS), poly(styrene‐b‐ethylene‐co‐propylene) (SEP), and two types of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS), which differ in their molecular weights on morphology and selected mechanical properties of immiscible polypropylene/polystyrene (PP/PS) 70/30 blend were investigated. Three different concentrations of styrene/rubber block copolymers were used (2.5, 5, and 10 wt %). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the phase morphology of blends. The SEM analysis revealed that the size of the dispersed particles decreases as the content of the compatibilizer increases. Reduction of the dispersed particles sizes of blends compatibilized with SEP, SBS, and low‐molecular weight SEBS agrees well with the theoretical predictions based on interaction energy densities determined by the binary interaction model of Paul and Barlow. The SEM analysis confirmed improved interfacial adhesion between matrix and dispersed phase. The TEM micrographs showed that SBS, SEP, and low‐molecular weight SEBS enveloped and joined pure PS particles into complex dispersed aggregates. Bimodal particle size distribution was observed in the case of SEP and low‐molecular weight SEBS addition. Notched impact strength (a_k), elongation at yield (ε_y), and Young's modulus (E) were measured as a function of weight percent of different types of styrene/rubber block copolymers. The a_k and ε_y were improved whereas E gradually decreased with increasing amount of the compatibilizer. The a_k was improved significantly by the addition of SEP. It was found that the compatibilizing efficiency of block copolymer used is strongly dependent on the chemical structure of rubber block, molecular weight of block copolymer molecule, and its concentration. The SEP diblock copolymer proved to be a superior compatibilizer over SBS and SEBS triblock copolymers. Low‐molecular weight SEBS appeared to be a more efficient compatibilizer in PP/PS blend than high‐molecular weight SEBS. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 291–307, 1999     

Compatibilization of poly(vinyl chloride)/polystyrene blends with epoxidized styrene-butadiene-styrene block copolymers

The effectiveness of epoxidized styrene-butadiene-styrene (ESBS) block copolymer as a polymeric compatibilizer for the incompatible polystyrene/poly(vinyl chloride) (PS/PVC) blend was investigated. ESBS at two epoxidation levels (34 and 49 mol% oxirane units) was used and the study covered mainly compositions with up to 30 wt% PS content in the ternary blends. The results support the view that ESBS can serve as a compatibilizer at these levels of epoxidation and when added in amounts in excess of 5 wt%. Ternary blends may also have good elongation properties due to the thermoplastic elastomer character of ESBS.     

Compatibility study of chlorinated polyethylene/ethylene methacrylate copolymer blends using thermal,mechanical, and chemical analysis

Blends of chlorinated polyethylene (CPE) elastomer and ethylene methacrylate copolymer (EMA) in various compositions were studied for their compatibility using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and Fourier transform infrared (FTIR) spectroscopy techniques. Irrespective of measurement techniques used, all blends showed a single glass transition temperature (T_g) lying in between the T_g of control polymers in both DSC and DMA. Glass transition temperatures of blends obtained from DSC were in consistency with Couchman–Karasz equation. Also, the T_g obtained from both DSC and DMA are above the “rule of mixing” line of the two control polymers. These results from thermal analysis clearly indicate some compatibility between the two polymers. Furthermore, compatibility of CPE/EMA blends were also been investigated by FTIR spectroscopy and scanning electron microscopic analysis. A shifting of characteristic C? Cl stretching peak of CPE and C?O stretching peak of EMA toward lower wave number indicate the presence of specific interaction between the two polymers. Mechanical properties like tensile strength, modulus at 100% elongation, elongation at break, and hardness were observed above the line of additivity drawn between the two control polymers, which corroborate compatibility between CPE and EMA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40316.     

Compatibilization of PP/PE blends and scraps with Royalene: Mechanical properties,SAXS, and WAXS

PP/PE 93/7 model virgin blends and recycled scraps were compatibilized with Royalene (EPDM/PE 65/35 blend) and mechanically tested. No differences in impact and tensile properties between them were found. However, the tensile-impact strength increased almost twice with 10%-compatibilized sample in comparison with uncompatibilized ones. The yield stress of blends containing 10% Royalene decreased to 75–80% of the original value. This effect is in agreement with microhardness measurements; the increase in the compatibilizer content causes softening of the blend. The elongation at break and elongation at yield do not depend on the compatibilizer concentration. The compatibilizer does not influence the degree of crystallinity (WAXS data) of the blends either. Vickers microhardness is in good agreement with Tabor's relationship. The differences between long periods of HDPE in Royalene and LDPE in PP/PE blends (SAXS) proved PE/EPDM interaction. The interaction plays a key role in the toughening of PP/PE blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Toughening mechanism in polyoxymethylene/thermoplastic polyurethane blends

In order to better understand the toughening mechanism in polyoxymethylene (POM)/thermoplastic polyurethane (TPU) blends and obtain ‘super‐toughened’ POM, we carried out an investigation on the notched impact strength, fractured surface, inter‐particle distance and spherulite size of POM as a function of the TPU content. A compatibilizer, namely polystyrene‐block‐poly(ethylene–butylene)‐block‐polystyrene, grafted with maleic anhydride (SEBS‐graft‐MA), was used to enhance the interfacial interaction between the POM and TPU. The impact strength is found to increase in two steps as a function of TPU content, namely a linear increase at the very beginning, and then a jump of impact strength is seen when the TPU content is larger than 30 wt%. A ‘supertough behavior’ is not observed for POM/TPU blends at room temperature, but can be achieved after adding 5 wt% of SEBS‐graft‐MA as the compatibilizer. The impact strength was found to depend not only on the interparticle distance but also on the interfacial interactions between POM and TPU. The dependence of impact strength on crystal size is considered for the first time, and a single curve is constructed, regardless of the composition and interfacial interactions. Our results indicate that the crystal size of POM indeed plays a role in determining the toughness, and has to be considered when discussing the toughening mechanism. Copyright © 2004 Society of Chemical Industry     

Synthesis and evaluation of compatibilizer based on interpenetrating polymer networks (IPN) for PET/LDPE blends

The present work considers the evaluation of recycled polymers, which are generally incompatible and are degraded during recycling with fatal consequences to their thermal and mechanical properties. Regarding this subject, the synthesis of a new compatibilizer in network form was carried out in order to counter such incompatibility. In this sense, low density polyethylene (LDPE) and poly(ethylene terephthalate) (PET) were compatibilized via the implementation of an interpenetrating polymer network (IPN), which was specifically synthesized to possess chemical groups that are akin to both plastics, PET and LDPE. The effects of the relative amount of poly(acrylic acid) (PAA) in the compatibilizer and the amount in the blends of PET/LDPE were evaluated. The results show that mechanical properties and interfacial adhesion of PET/LDPE blends were modified and improved with the addition of the synthesized compatibilizer compared with a commercial compatibilizer (polyethylene grafted with maleic anhydride, PE‐g‐AA). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43704.     

Effect of molecular structure of styrene–butadiene block copolymers on morphology,rheological properties,and impact strength of polystyrene/polyethylene blends

The effect of molecular structure of six model styrene–butadiene (SB) block copolymers with various number of blocks and two lengths of styrene blocks on morphology, rheological properties, and impact strength of polystyrene (PS)/high‐density polyethylene (PE) blends was studied. It was found that location of SB copolymers in the blends is determined by the length of styrene blocks. The length of styrene blocks has similar effects on impact strength and linear viscoelastic properties of the blends. On the other hand, the correlation was not found between the effects of a number of blocks on impact strength and linear viscoelastic properties of the blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2303–2309, 2003     

Effects of fillers,maleated ethylene propylene diene diene rubber,and maleated ethylene octene copolymer on phase morphology and oil resistance in natural rubber/nitrile rubber blends

The phase morphology and oil resistance of 20/80 NR/NBR blends filled with different types of fillers and copolymers were investigated. In the case of filler effect, N220, N330, and N660 carbon blacks with different particle sizes were used. Additionally, the blends filled with nonblack‐reinforcing fillers, that is, precipitated and silane‐treated silica, were investigated. To study the compatibilization effect, maleated ethylene propylene diene rubber (EPDM‐g‐MA) and maleated ethylene octene copolymer (EOR‐g‐MA) were added to the blends. The results revealed that the addition of filler, either carbon black or silica, to the blend caused a drastic decrease in NR dispersed phase size. Carbon blacks with different particle sizes did not produce any significant difference in NR dispersed phase size under the optical microscope. Silica‐filled blends showed lower resistance to oil than did the carbon black–filled blends. In addition, it was determined that neither EOR‐g‐MA nor EPDM‐g‐MA could act as a compatibilizer for the blend system studied. The oil resistance of the blends with EPDM‐g‐MA is strongly affected by the overall polarity of the blend. In the case of EOR‐g‐MA, the oil resistance of the blends is significantly governed by both overall polarity of the blend and phase morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1156–1162, 2003     

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 developed in twin screw extrusion

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 (PA6) were developed in twin screw extrusion. The rubber was cured with SP 1045 methylol phenolic resin during melt mixing in twin screw. Effect of degree of carboxylation in the rubber phase on blend properties has been assessed. Phase morphologies have been characterized using transmission electron microscopy. A compatibilizing NBR‐g‐Nylon 6 graft copolymer generated in situ during melt mixing via interfacial reaction between the ? COOH groups in NBR and the ? NH₂ end groups in nylon 6 has been effective in generating a fine and stable dispersion of the rubber within the polyamide matrix. The graft copolymer has been characterized by DMTA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 372–377, 2007     

Influence of premade and in situ compatibilizers in polypropylene/ethylene–propylene–diene terpolymer thermoplastic elastomeric olefins and thermoplastic vulcanizates

During dynamic vulcanization of polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM) blends with dicumyl peroxide/triallyl cyanurate, there is a possibility of the generation of in situ graft links at the interface. Three potential compatibilizers (PP‐grafted EPDM, styrene–ethylenebutylene–styrene, and trans‐polyoctenamer) for PP/EPDM blends were first investigated as references to obtain a quantified insight into the effects to be expected from in situ graft links. Only the first compatibilizer showed some compatibilizing action in straight, unvulcanized blends, as evidenced by a slight increase in the tensile strength of the blend and a somewhat smaller EPDM particle size within the PP matrix. Also, dynamic mechanical testing, in particular, the glass‐transition temperatures of the PP and EPDM components, showed some signs of compatibilization. The PP‐grafted EPDM resembled most closely the structures of PP and EPDM. In the spectra obtained with high temperature, solid‐state NMR, there was an indication that PP–EPDM graft links were generated during the dynamic vulcanization process that still remained after the extraction of the free PP phase from the thermoplastic vulcanizate film. NMR relaxation experiments gave further evidence for the graft links formed in situ. In all cases, only qualitative indications could be achieved because of the extremely low number of graft links formed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3877–3888, 2006