Ultraviolet irradiation of poly(vinyl chlorides). Part I. Effect of substituents on radiation parameters

The crosslinking and main-chain scission of PVC and its derivatives by ultraviolet radiation at 2537 A. were investigated. Examination of the relationship between gel fraction and radiation dose showed that the number of crosslinks formed in pure PVC per 100 e.v., G_c., was 0.29 and did not vary greatly from pure PVC to commercial PVC. However, the efficiency of scission was lowest (G_s = 0.06) for purified PVC, increased to 0.23–0.26 for commercial PVC, and increased further when chelates were substituted on PVC at C1 atoms. G_s for PVC with opper thalocyanine was 0.62, with copper salicylate was 1.38, and was 6.20 with ferrocene. G_c values also increased in the same order, from 0.40 to 3.10. The ratio of main-chain fractures to number of crosslinks formed (β/α) increased again in this order from 0.1 for purified PVC to 1.0 for PVC–ferrocene. For purified PVC, β/α increased after 36 hr. of ultraviolet irradiations. In the presence of copper salicylate and ferrocene, ion-radical reactions probably contribute towards the high β/α ratio. Ability of the aromatic substituents to enter chain–transfer reactions with polymeric radicals followed by coupling reactions may contribute partly towards crosslinking in PVC.     

Enhancement of Photostabilization of Poly(vinyl chloride) Doped with Sulfadiazine Tin Complexes

New sulfadiazine tin complexes were synthesized in 67–80% yields from the reaction of sulfadiazine, and different organotin(IV) chlorides and their structures were established. The synthesized complexes were used as additives at a low concentration (0.5% by weight) to enhance poly(vinyl chloride) (PVC) photostability. The PVC samples containing sulfadiazine tin complexes (thickness = 40 μm) were fabricated and irradiated with ultraviolet light at room temperature for 300 h. The changes that occurred within the PVC samples upon irradiation were investigated by inspecting the loss in weight, reduction in the average molecular weight, formation of small degradation fragments containing polyene, carbonyl, and hydroxyl moieties, and changes in the ultraviolet absorption intensity of polymeric materials. The surface morphology of irradiated PVC samples was investigated using optical, atomic force, and scanning electron microscopies. There were lesser changes within the PVC samples with sulfadiazine tin complexes compared to the blank PVC sample. The dimethyltin(IV) complex was found to be the most efficient additive in stabilizing PVC against irradiation. The role played by the complexes in reducing the photodegradation of PVC was investigated, and a mechanism was proposed. J. VINYL ADDIT. TECHNOL., 26:370–379, 2020. © 2019 Society of Plastics Engineers     

Irradiation Modification of PVC/NBR Blend

Electron beam initiated cross-linking on the 50/50 poly(vinyl chloride), PVC/acrylonitrile butadiene rubber, NBR blend was studied in the absence and presence of 4 phr trimethylolpropane triacrylate (TMPTA). The 50/50 NBR/PVC blend was prepared by mixing in a Brabender Plasticoder at 170°C. The blend was then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 200 kGy in air and room temperature. The changes in gel fraction, tensile strength, hardness, impact strength, scanning electron micrographs and dynamic mechanical properties of the samples were investigated. The gel fraction results indicate that under the irradiation conditions employed, the PVC/NBR blend cross-linked by electron beam irradiation. The addition of TMPTA was found to be effective in the acceleration of the radiation-induced cross-linking. Gradual increases in mechanical properties with irradiation dose were observed before exhibiting a decline due to embrittlement as a consequence of excessive cross-linking at higher irradiation doses. The gradual changeover from ductile to brittle fracture due to the irradiation-induced cross-linking was evident from the SEM examination The increase in the storage modulus and T_g as well as the reduction in the damping peak with the increase in irradiation dose reveal that the enhancement in mechanical properties of NBR/PVC blends upon irradiation is due to the irradiation-induced cross-linking, as well as the improved interaction between NBR and PVC.     

Photostability,thermal and mechanical properties of poly(vinyl chloride)/novel acrylate terpolymer blend

Methyl methacrylate/2‐hydroxyethyl methacrylate/maleic anhydride terpolymer with various compositions was synthesized, characterized and investigated as a photostabilizer for rigid polyvinyl chloride (PVC). The chemical structure of the terpolymer MMA/HEMA/MA, was confirmed by ultraviolet–visible and FTIR, spectroscopy. The molecular weights of the terpolymer were determined by applying gel permeation chromatography. The stabilizing efficiency of the terpolymer was evaluated by the determination of the weight loss of PVC/terpolymer blends after various irradiation times. The content of the formed gel as well as the intrinsic viscosity of the soluble fraction of the photodegraded polymer were also determined. The efficiency was also evaluated by measuring the extent of the discoloration of the photodegraded polymer. Thermal gravimetric analysis of the terpolymer and PVC/terpolymer blend were measured. Moreover, physicomechanical properties of photodegraded stabilized PVC samples were as well measured. The results revealed that the photostabilizing efficiency as well as thermal stability increased in the presence of the terpolymer as blended with PVC and by the increase of maleic anhydride ratio in the terpolymer. The photostabilizing efficiencies were compared with the industrially known UV absorber 2‐hydroxy‐4‐(octyloxy) phenylbenzophenone. J. VINYL ADDIT. TECHNOL., 25:E55–E62, 2019. © 2018 Society of Plastics Engineers     

Fourier transform infrared studies of poly(vinyl chloride) blends with ethylene Co- and terpolymers

The miscibility of poly(vinyl chloride) (PVC) with various ethylene copolymers and terpolymers were investigated using FT-IR spectroscopy. All blends reported were 50/50 by weight. In blends of PVC with ethylene/dimethyl acrylamide copolymer (E/DMA), frequency shifts were observed in the amide carbonyl (proton acceptor) and the α-hydrogen of PVC (proton donor) characteristic bands. In blends of PVC with ethylene/ethyl acrylate/carbon monoxide terpolymer (E/EA/CO), both the ester carbonyl and the ketone carbonyl characteristic frequencies showed mutual shifts and appeared as if they merged together. Small frequency shifts were also observed in the α-hydrogen of PVC characteristic bands. In blends of PVC with ethylene/vinyl acetate/carbon monoxide terpolymer (E/VA/CO), the ester carbonyl frequency showed a shift while that of the ketone carbonyl was essentially unchanged. On the other hand, in PVC blends with ethylene/vinyl acetate copolymer (E/VA), the ester CO frequency did not show any shift, which is consistent with their observed immiscibility. Thus, it is clear that incorporating a ketone ? C?O in ethylene/ester copolymers to form the corresponding terpolymers enhances their miscibility with PVC as earlier proposed on the basis of dynamic mechanical studies. Similar results were shown for blends of PVC with ethylene/2 ethyl hexyl acrylate/carbon monoxide terpolymer (E/2EHA/CO). Frequency shifts imply specific interactions which suggest polymer-polyer miscibility on a molecular scale.     

Effect of additive concentration and gamma radiation on the molecular and color properties of poly(vinyl chloride)

The effects of addition of different monomers on the molecular properties of poly(vinyl chloride) (PVC) have been studied. Three different additive monomers from N‐phenyl maleimide derivatives were added with the same concentration 0.02 gm/1 gm PVC as stabilizers to PVC. These stabilizers are N‐phenyl maleimide, Para‐carboxy N‐phenyl maleimide, and Para‐amide carboxy N‐phenyl maleimide (PA‐NPMI). Their stabilizing efficiencies were evaluated by measuring the intrinsic viscosity of the solution samples. The results reveal that the type of the additive monomer plays a major role in determining the stabilizing potency of these materials. It was found that the PA‐NPMI is the most effective stabilizer that improves the intrinsic viscosity of pure PVC from 1.02 to 1.19. So, the effect of its addition with different concentrations was studied. The results indicate that the sample with 0.015 gm PA‐NPMI/1 gm PVC has higher intrinsic viscosity. Thus, this sample was chosen to be a subject for further study to investigate the effect of gamma irradiation on its molecular and color properties. Samples from the 0.015 gm PA‐NPMI/1 gm PVC were irradiated with gamma doses in the range 5–100 kGy. It is found that the irradiation in the dose range 20–60 kGy enhances the intrinsic viscosity of the samples. In addition, the transmission of these irradiated samples in the wavelength range 200–2500 nm, as well as any color changes, was studied. The color intensity ΔE was greatly increased with increasing the gamma dose, and was accompanied by darkness with a significant increase in the yellow color component. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of UV absorber on photodegradation processes of poly(vinyl chloride) with different average degrees of polymerization

The influence of UV absorber (Chimassorb81) on the photodegradation mechanism of different average degrees of polymerization (DP ) of poly (vinyl chloride) (PVC) with UV‐irradiation time was investigated by viscosity‐average molecular weight determination, UV‐vis spectroscopy, FTIR, contact angle measurement, and scanning electron microscopy (SEM). The PVC films with different DP (1000 and 3000), which contained 0.3 or 0.5 phr Chimassorb81, were prepared by solution casting. It was carried out by exposing specimens to xenon‐arc light source with a spectral irradiance of 0.68 W/(m² nm) at 63°C. It is found that the Chimassorb81 is efficient photostabilizer for PVC with different DP . Although the Chimassorb81 delays the photodegradation of PVC, it does not influence the photodegradation mechanisms of PVC with different DP . The main photodegradation reaction for the lower DP of PVC is dehydrochlorination in the initial stage of UV‐irradiation, and then the crosslinking and chain scission reactions occurred after long irradiation. However, the main reaction of the higher DP of PVC is not dehydrochlorination but crosslinking and chain scission in the initial stage of UV‐irradiation. The results of carbonyl index, C? Cl index, contact angle measurement, and SEM also show that the photostability of Chimassorb81 is more effective for the higher DP of PVC, especially in the presence of higher concentration of Chimassorb81. POLYM. ENG. SCI., 47:1480–1490, 2007. © 2007 Society of Plastics Engineers     

紫外线交联PVC的研究

通过二乙基二硫代氨基甲酸钠（铜试剂）取代PVC上的部分氯原子，在PVC分子链上引入光敏原因，在紫外线照射下，PVC分子可发生交联反应形成交联产物，实验研究了铜试剂用量，接枝反应温度和时间以及紫外光辐照时间对PVC凝胶含量及力学性能的影响，在1kW高压汞灯距试样0.5m、辐照2h的最佳交联条件下，可得到凝胶含量超过83%的产联产物。     

Effect of epoxy resin on thermal,dynamic, and mechanical properties of rigid poly(vinyl chloride)

This work is concerned with the effect of an epoxy resin on the properties of rigid poly(vinyl chloride) (PVC). The epoxy resin concentrations of 0, 1, 2, 4, and 6 phr were used to prepare PVC/epoxy polymer blends and the viscoelastic behavior of the blends was investigated by dynamic mechanical thermal analysis and rheometry test. The results revealed that the low molecular weight epoxy resin did not greatly affect the viscoelastic properties of PVC. From the morphological point of view, the smallest droplet size of epoxy dispersed in the polymer blends was found in the sample with 1 phr epoxy resin, and the largest one was for the sample with 6 phr epoxy. The thermal properties of PVC/epoxy blends were investigated using differential scanning calorimetry and thermogravimetric analysis, as well. According to our research, the initial decomposition temperature of PVC was increased about 6°C by the incorporation of epoxy resin. The results of tensile test showed that the addition of epoxy resin decreased the elongation‐at‐break of PVC about 50% in the samples without calcium carbonate and about 25% in the samples containing calcium carbonate. Moreover, the failure mode of PVC was changed from a ductile fracture mode to a brittle fracture mode with the addition of epoxy resin. J. VINYL ADDIT. TECHNOL., 25:E72–E79, 2019. © 2018 Society of Plastics Engineers     

Study of poly(vinyl chloride)/acrylonitrile–styrene–acrylate blends for compatibility,toughness, thermal stability and UV irradiation resistance

A novel rigid poly(vinyl chloride) (PVC)/acrylonitrile–styrene–acrylate (ASA) copolymer blend with good ultraviolet (UV) irradiation resistance and toughness was reported. ASA with good weatherability and toughness was mixed with PVC by conical twin‐screw extruder to improve the UV irradiation resistance and toughness of PVC. The blends were characterized using Fourier‐transform infrared spectra, dynamic mechanical analysis, and scanning electron microscope. Notch Charpy impact test was used to characterize the UV radiation induced changes in toughness. The results showed that ASA was able to toughen PVC with simultaneously improving heat resistance, thermal stabilization, and protecting PVC from irradiation photochemical degradation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2143–2151, 2013     

Reaction of poly(vinyl chloride) with ethylenediamine hydrotrisulphide and properties of the products

The chemical structure and the properties of the products of the reaction of poly(vinyl chloride) (PVC) with ethylenediamine hydrotrisulphide were investigated. PVC derivatives containing a polysulphide crosslinkage and a hydropolysulphide pendant (PSC-PVC) were obtained by the reaction of PVC with ethylenediamine hydrotrisulphide in ethylenediamine (EN) as well as in EN-diglyme, and EN-benzene at 20–50°C for 0.5–5h. The chemical structure of PSC-PVC was determined from crosslinking density before and after iodine oxidation and elemental analysis. Scission of polysulphide crosslinkage in PSC-PVC by some thiols was carried out in tetrahydrofuran-triethylamine solution at 30°C for 1–4h as well as in a hot roller mill at 125–180°C for 2–8 min. The former product was photocrosslinked under ultra-violet irradiation in air and the latter showed the properties of a plastic, a leather, and a rubber with increasing weight of dioctyl phthalate.     

Radiation crosslinking of poly(vinyl chloride) with trimethylolpropanetrimethacrylate. IV. Effect of diundecyl phthalate: Dependence of physical properties on composition

Blends of poly(vinyl chloride) (PVC) with polyfunctional monomers may be crosslinked by ionizing radiation. The physical properties of PVC blended with trimethylolpropanetrimethacrylate (TMPTMA) and diundecyl phthalate (DUP) were studied. The TMPTMA monomer crosslinked the blend by homopolymerization and/or grafting to PVC. The plasticizer, DUP, was chemically inert under irradiation but, by plasticizing the macromolecules and diluting the monomer, changed the kinetics extensively. Characteristics of the glass transitions and the tensile mechanical properties have been correlated with blend composition and radiation dose. Before irradiation, poly(vinyl chloride) was plasticized by both DUP and TMPTMA monomer. The increase in glass transition temperature and mechanical strength following irradiation to 5 Mrad was correlated with the TMPTMA content of the blend. Both the molecular structure of the network and the DUP content of the blend were factors in determining the physical properties of the final crosslinked blend. The molecular structure was determined by the kinetics of the crosslinking reactions, which in turn were determined by the blend composition. A molecular interpretation consistent with the physical properties, chemical kinetics, and mechanism of the crosslinking system has been presented.     

The surface modification of diatomite,thermal, and mechanical properties of poly(vinyl chloride)/diatomite composites

Pristine diatomite was first purified by acid treatment and then modified with γ‐methacryloxy propyl trimethoxysilane molecule (KH570) to introduce hydrophobic chains on the surface of acid‐treated diatomite. Fourier‐transform infrared spectroscopy and thermogravimetric analysis (TGA) indicated that the silane coupling agent (KH570) was successfully grafted on the diatomite through covalent bonding. The digital photos showed that the silanization process changed the surface property of the diatomite. The poly(vinyl chloride) (PVC)/pristine diatomite and PVC/modified diatomite composites were prepared via two‐roll mill. The thermal stability and mechanical properties of PVC composites were investigated by TGA, mechanical properties tests, and dynamic mechanical analysis. The results showed that the thermal stability of the composites improved and maximum weight loss temperature (T_max) of the PVC composite with 1 phr modified diatomite was about 20°C higher than that of PVC composite without diatomite. The PVC/modified diatomite composites exhibited better mechanical properties owing to the stronger interfacial interaction between PVC matrix and modified diatomite. But the impact strength reduced sharply when the addition of diatomite was more than 1 phr. The reason of the phenomenon is that the diatomite plays the role of defects in PVC and it works against the absorption of impact strength energy. It was proved by the results of scanning electron microscopy. J. VINYL ADDIT. TECHNOL., 25:E39–E47, 2019. © 2018 Society of Plastics Engineers     

紫外光辐照对硬质聚氯乙烯结构及性能的影响

采用衰减全反射傅立叶变换红外光谱、紫外光谱、扫描电镜、凝胶渗透色谱、拉伸应力一应变、黄色指数、与水接触角及失重率等测试研究了紫外光(UV)辐照对硬质聚氯乙烯(PVC)结构及性能的影响。结果表明:随着UV辐照时间的延长,平均相对分子质量增大至最大值后,进一步延长辐照时间平均相对分子质量减小,多分散系数由1.771增加到1.919,相对分子质量分布变宽。分子链中引人了多种揣基官能团和多种共扼多烯结构。试样表面经历了粗糙、裂纹形成及其扩散等形态破坏过程,试样黄色指数由40.7%逐渐增加到90%以上,表面颜色逐渐变深,失重率逐渐增大到0.22%,与水接触角先由63.3迅速下降到55,然后下降程度趋于平缓,逐渐下降到平衡值50UV辐照的初期试样的拉伸强度由未经辐照时的55MPa增加到57MPa,进一步延长辐照时间后拉伸强度降低,而断裂伸长率由未辐照时的35.5%迅速降低到11.8%。     

Synthesis and characterization of gallic acid derivatives and their utilized as organic photo-stabilizers for poly (vinyl chloride)

The photo-stabilization of poly (vinyl chloride) containing 1,3,4-thiadiazole derivatives derived from Gallic acid as additives were studied. The four different substituents of 1,3,4-thiadiazole-gallic derivatives, 2-(4-substituted-phenyl)-5-(3,4,5-trimethoxyphenyl)-1,3,4-thiadiazole, (R1-R4) were prepared starting from Gallic acid and characterized by FTIR, ¹HNMR and elemental analysis. The 5% concentration by weight of these derivatives (R1-R4) in PVC polymer was used to study the photo-stabilization of PVC. The photo-stabilization of PVC films were studied at room temperature under irradiation of U.V light with λ = 385 nm and an intensity of 7.75 × 10^?7 Einstein dm^?3 s^?1. The photo-stabilization activity of these compounds was determined by monitoring the carbonyl (I_CO), polyene (I_po) and hydroxyl (I_OH) indices and weight loss method with irradiation time. It was found that the (I_CO), (I_po) and (I_OH) index values increased with the irradiation time increase, this increase found to depend on the type of additives, also it was found that the PVC films in the presence of additives (R1-R4) were arranged as the following trend: PVC + R1 > PVC + R2 > PVC + R3 > PVC + R4.     

Different photodegradation processes of PVC with different average degrees of polymerization

The influence of ultraviolet (UV)‐irradiation on the photodegradation mechanism of different average degrees of polymerization (DP ) of poly(vinyl) chloride (PVC) with UV‐irradiation time was investigated by viscosity‐average molecular weight determination, UV‐vis spectroscopy, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), contact angle measurement, and scanning electron microscopy (SEM). PVC films with different DP (800, 1000, 1300, 3000) were prepared by solution casting. It was carried out exposing specimens to a xenon‐arc light source with a spectral irradiance of 0.68 W/(m² ·nm) at 63°C. It was found that the photodegradation mechanism of the lower DP of PVC (DP = 1000) was different from the higher DP of PVC (DP = 3000). This was because the lower DP of PVC was a homopolymer, while the higher DP of PVC was often produced by copolymerizing with a certain quantity of crosslinking agent (e.g., DAP and DAM). UV‐vis and FTIR spectroscopy studies provided some results concerning the structure of the irradiated PVC, and the carbonyl index and C? Cl index were induced to study the process of PVC photodegradation with different DP . TGA showed that the degradation temperatures of different weight loss increased with the irradiation time. The surface morphology of the irradiated polymer films with different DP was observed by contact angle measurement and SEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The effect of irradiation surface treatment of UHMWPE fibre on the interfacial properties of PVC composite

Irradiation surface modification method was used for the surface treatment of ultrahigh molecular weight polyethylene (UHMWPE) fibre to improve the interfacial adhesion of the UHMWPE fibre reinforced PVC composite. The surface characteristics of untreated and treated UHMWPE fibre were characterised by XPS and Fourier transform infra-red spectroscope. The friction and wear properties of the PVC composites filled with differently surface-treated UHMWPE fibres (20?vol.-%), were investigated on a ring-on-block tribometer. Experimental results revealed that irradiation treatment largely increased the mechanical properties of UHMWPE fibre/neoprene/PVC (UF/N/PVC) composites. Scanning electron microscope investigation of worn surfaces of PVC composites showed that surface-treated UF/N/PVC composite had the strongest interfacial adhesion.     

Crosslinking of polyvinyl chloride by electron beam irradiation in the presence of ethylene–vinyl acetate copolymer

Electron beam (EB) irradiation of polyvinyl chloride (PVC) was carried out in the presence of three different ethylene–vinyl acetate copolymers (EVA). The mechanical properties of the original and irradiated blends were tested. The gel content measurement, chlorine loss upon electron irradiation, and gel permeation chromatograph (GPC) were used to characterize the effect of EVA on the irradiation behavior of PVC/EVA blends. The content and the chemical structure of EVA in the blends had considerable effects on the mechanical properties and gel content of the blends. The incorporation of EVA into PVC blend can increase the gel content and reduce chlorine loss of the blends. The GPC analysis of the soluble part in the irradiated PVC samples showed that the addition of EVA into the PVC blend lowered the polydispersity of molecular weight of PVC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1571–1575, 2004     

Thiazole derivatives‐functionalized polyvinyl chloride nanocomposites with photostability and antimicrobial properties

Polyvinyl chloride (PVC) was modified via substitution reaction with 2‐aminothiazole and ethyl 2‐aminothiazole‐4‐carboxylate separately in the absence and in presence of silver (AgNPs) or copper (CuNPs) nanoparticles, using metal salts as precursors, in 3% (w/w) with respect to PVC. The functionalized PVC‐nanocomposites have been characterized via FTIR, ¹HNMR spectroscopic analyses, in addition to the morphological investigation such as scanning (SEM) and transmission electron microscopy (TEM). Spectral data confirmed the introduction of the thiazole (ester) to the PVC backbone. TEM analysis showed that the sizes of the AgNPs and CuNPs have fallen in the range of 10–30 nm and 30–50 nm for the prepared nanocomposites, respectively. Evaluating the photostability of modified nanocomposites was estimated by following the extent of discoloration for UV‐irradiated samples colorimetrically in accordance with the irradiation time. The antimicrobial activity of the modified nanocomposites was explored against three Gram+ve bacteria (Bacillus subtilis, Staphylococcus aureus, and Streptococcus faecalis), three Gram‐ve bacteria (Escherichia coli, Neisseria gonorrhoeae, and Pseudomonas aeruginosa), and two fungi (Candida albicans and Aspergillus flavus). Aminothiazole (ester)‐functionalized PVC exhibited significant antimicrobial efficiencies against the investigated pathogens. However, incorporation of AgNPs or CuNPs to the modified PVC enhanced their inhibitory effect against the microorganisms under investigation. J. VINYL ADDIT. TECHNOL., 25:E137–E146, 2019. © 2018 Society of Plastics Engineers     

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.