【作者】 刘辉；

【导师】 陈蕴智；

【作者基本信息】 天津科技大学 ， 印刷与包装工程， 2021， 博士

【摘要】 近年来我国电商行业发展迅猛,快递行业业务量出现了暴涨,在带动经济发展的同时也带来了纸箱、塑料袋、泡沫塑料、缓冲材料和胶带等包装材料的巨大消耗。快递包装废弃物导致了严重的环境污染和资源浪费,为了解决这一问题国家出台了一系列政策,要求快递行业应当按照规定使用环保材料对邮件快件进行包装,优先采用可重复使用、易回收利用的包装物,优化邮件快件包装,减少包装材料的使用。胶带作为一种使用量大且难以回收和降解的快递包装材料,一直是制约快递包装行业绿色发展的痛点。因此,研发一种新型环境友好型胶带是大势所趋。本研究探究制备一种可水溶解、可降解的胶带,能够满足快递包装绿色发展、循环发展和低碳发展的要求,为胶带废弃物的回收处理提供有利条件。胶带的改性制备主要包括基材的制备和压敏胶的制备,首先通过纳米改性的方法提升聚乙烯醇基材的各项性能,其次通过增塑的方法对聚乙烯吡咯烷酮压敏胶的性能进行改进。具体改进方法为:首先,使用酸活化、有机插层和机械作用相结合的方法对层状硅酸盐蛭石进行插层和剥分处理,进一步将剥分蛭石与聚乙烯醇通过共混的方式制备出复合薄膜,使纳米蛭石能够有效发挥作用,提升聚乙烯醇薄膜的性能并将其用做胶带的基材。其次,以聚乙烯吡咯烷酮为原料制备双组分压敏胶,确定其最佳的制备配方和条件。最后探究新型胶带的基本性能和可降解性,使其能够有效解决由于胶带大量使用所造成的环境污染和废弃物回收处理等问题。主要研究结果如下:（1）使用不同浓度的盐酸对蛭石（VMT）进行活化,在此基础上再使用十六烷基三甲基溴化铵（CTAB）对其进行有机插层,最后在机械力的作用下对插层蛭石进行剥分。盐酸活化蛭石的红外光谱图中Si-OH伸缩振动和结晶水中的-OH伸缩振动峰向低波数方向移动;小角X射线衍射的结果显示蛭石的晶面间距增大,晶体结构不稳定。当盐酸浓度为0.006mol/L时,蛭石的阳离子交换量（CEC）达到最大值为55.78cmol/kg;Zeta电位值达到最小值14.5m V。有机插层蛭石的红外测试结果显示CTAB能够进入到蛭石的层间结构中;小角X射线衍射测试结果显示经过有机插层处理的蛭石的晶面间距明显变大。当插层剂CTAB的溶液浓度达到3倍CEC时,CTAB在蛭石中的插层达到完全。机械剥分后蛭石的粒径从48.56μm减小至0.69μm。（2）将剥分蛭石按照不同的质量比添加到PVA薄膜中,随着VMT-PVA复合薄膜中蛭石质量比的不断增大,复合薄膜的力学性能和阻隔性能呈现出先增大后减小的趋势。当蛭石添加量为2.0%时,VMT-PVA复合薄膜的拉伸强度达到最大值65.3MPa;当蛭石添加量为2.5%时,VMT-PVA复合薄膜的水接触角达到最大值69.2°,材料的亲水性明显下降;当水溶温度为50℃时,VMT-PVA复合薄膜的失重率均保持在16%-17%之间,与纯PVA相比,复合薄膜的耐水性得到提升。VMT-PVA复合薄膜的红外光谱特征峰发生红移,表明材料内形成了氢键作用且形成了新的界面层或者局部高分子网络结构。X射线衍射测试结果表明VMT-PVA复合薄膜的结晶度随着蛭石添加量的增大呈现出先增大后减小的趋势,当蛭石添加量达到2.0%时,复合薄膜的结晶度达到55.88%。DSC测试结果显示复合薄膜的玻璃化转变温度和熔融温度得到提高。TG测试结果发现复合薄膜的分解终止温度提高了6.7℃-20.5℃,蛭石添加量在2.0%以下时,能够有效提高VMT-PVA复合薄膜的热稳定性能。SEM测试结果显示低添加量蛭石在PVA基体中分散均匀,蛭石纳米粒子的直径约为80nm,但是随着蛭石添加量的不断增大,蛭石粒子在PVA基体中会出现团聚和分散不均匀等问题,进而导致材料性能的下降。（3）为了得到水性压敏胶的最佳制备条件,分别对压敏胶的制备过程进行了单因素实验和正交实验。实验结果发现压敏胶的最优制备配方和制备条件为:聚乙烯吡咯烷酮（PVP）水溶液浓度为30%、增塑剂SYCA添加量为30%、p H值为7、制备时间为2h。压敏胶的红外光谱中没有出现新的特征峰,表明压敏胶的组分之间没有发生化学反应。另外,-OH的伸缩振动峰从3422cm^-1移动至3356cm^-1,醇中C-O伸缩振动峰从1075cm^-1移动至1073cm^-1,表明压敏胶内部存在分子间氢键。压敏胶的核磁共振H谱结果进一步证实两种材料之间存在氢键作用。使用增塑剂SYCA对PVP水溶液进行增塑后,压敏胶的玻璃化转变温度降低至-67.5℃,常温下仍能处于高弹态,在不破坏粘性的同时提高了压敏胶的弹性。当压敏胶中的水分被烘干以后,其储能模量G’增大、损耗因子tanδ减小,压敏胶的内聚能强度得到显著提升。（4）新型水溶胶带的初粘性测试为9#钢球、持粘性测试为1.2mm/h,180°剥离强度和90°剥离强度分别为3.6N/cm和3.5N/cm,拉伸强度为88.8MPa,拉伸断裂应力为50.8N,断裂伸长率为145.1%,最大穿刺强度为62.4MPa,能够满足国家标准对封箱胶带的相关要求。胶带在水温80℃时的失重率达到78.21%,具有水溶性。在土埋降解模拟实验中,胶带最终的质量损失为30.39%;在堆肥实验中,胶带的最终生物分解率为63.8%,达到了国标的要求,具有可降解性。更多还原

【Abstract】 In recent years,China’s e-commerce industry has developed rapidly,so the business volume of express industry has soared.In the economic development,it also brought huge consumption of cartons,plastic bags,foam plastics,tape and cushioning materials.Express packaging waste leads to serious environmental pollution and waste of resources.In order to solve this problem,the state had issued a series of national standards and policies,requiring the express industry to use environmental protection materials to package the express mail according to the regulations,giving priority to reusable and recyclable packaging materials,optimizing the express mail packaging and reducing the use of packaging materials.As a kind of express packaging material with large usage and difficult to recycle and degrade,adhesive tape has always been a pain point restricting the green development of express packaging industry.Therefore,the development of a new type of environmentally friendly tape is the general trend.This study explored the preparation of a kind of water soluble and degradable adhesive tape,which can meet the requirements of green development,recycling development and low-carbon development of express packaging,and provide favorable conditions for the recycling of adhesive tape waste.The modification of adhesive tape mainly includes the preparation of substrate and pressure-sensitive adhesive.Firstly,the performance of polyvinyl alcohol is improved by nano modification,and then the performance of PVP pressure-sensitive adhesive is improved by plasticization.The specific improvement method is as follows:Firstly,the layered silicate vermiculite was intercalated and stripped by acid activation,organic intercalation and mechanical action.Furthermore,the composite film was prepared by blending the peeled vermiculite and polyvinyl alcohol,so that the nano vermiculite can play an effective role,improve the performance of polyvinyl alcohol film,and use it as the base material of adhesive tape.Secondly,PVP and plasticizer SYCA were used as raw materials to prepare two-component pressure sensitive adhesive,and the best preparation formula and conditions were determined.Finally,explore the basic performance and degradability of the new tape,so that it can effectively solve the problems of environmental pollution and waste recycling caused by the extensive use of tape.The main results are as follows:（1）Different concentrations of hydrochloric acid were used to activate vermiculite（VMT）,and then cetyltrimethylammonium bromide（CTAB）was used to intercalate it.Finally,the intercalated vermiculite was stripped by mechanical force.In the FTIR of hydrochloric acid activated vermiculite,the peaks of Si-OH stretching vibration and-OH stretching vibration in crystal water moved to low wavenumber.The results of small angle X-ray diffraction showed that the crystal plane spacing of vermiculite increased and the crystal structure was unstable.When the concentration of hydrochloric acid was 0.006mol/L,the CEC of vermiculite reached the maximum value of 55.78cmol/kg,and the Zeta potential reached the minimum value of 14.5m V.FTIR results of organic intercalated vermiculite showed that CTAB could enter into the interlayer structure of vermiculite.The results of small angle X-ray diffraction showed that the crystal plane spacing of vermiculite after organic intercalation was obviously larger.When the concentration of CTAB was 3 times CEC,the intercalation of CTAB in vermiculite was complete.After mechanical stripping,the particle size of vermiculite decreased from 48.56μm to 0.69μm.（2）With the increasing of the mass ratio of vermiculite in VMT-PVA composite film,the mechanical properties and barrier properties of the composite film first increased and then decreased.When the vermiculite content was 2.0%,the tensile strength of VMT-PVA composite film reached the maximum value of 65.3MPa.When the content of vermiculite was 2.5%,the water contact angle of VMT-PVA composite film reached the maximum value of 69.2°and the hydrophilicity of the material decreased.When the water solubility temperature was 50℃,the weight loss rate of VMT-PVA composite film was between 16%-17%,and the water resistance of the composite film was improved compared with pure PVA.The FTIR of VMT-PVA composite film showed a red shift,which indicated that a strong hydrogen bond was formed in the material and a new interface layer or local polymer network structure was formed.The results of X-ray diffraction showed that the crystallinity of VMT-PVA composite film increased first and then decreased with the increase of vermiculite content.When the vermiculite content reached 2.0%,the crystallinity of VMT-PVA composite film reached 55.88%.DSC results showed that the glass transition temperature and melting temperature of the composite films were improved.TG test results showed that the decomposition termination temperature of the composite film increased by 6.7℃-20.5℃.When the vermiculite content was less than 2.0%,the thermal stability of VMT-PVA composite film could be effectively improved.SEM test results showed that vermiculite with low content was uniformly dispersed in PVA matrix,and the diameter of vermiculite nanoparticles was about 80nm.However,with the increase of vermiculite content,the agglomeration and uneven dispersion of vermiculite lamellae in PVA matrix would occur,which would lead to the decline of material properties.（3）In order to obtain the best preparation conditions of water-based pressure sensitive adhesive,single factor experiment and orthogonal experiment were carried out.The results showed that the optimal formulation and preparation conditions were as follows:the concentration of PVP aqueous solution was 30%,the addition of plasticizer SYCA was 30%,the p H is 7,the preparation time are 2 hours.There was no new characteristic peak in the FTIR of PSA,which indicated that there was no chemical reaction between the components of PSA.The stretching vibration peak of hydroxyl group moved from 3422cm^-1 to 3356cm^-1.The stretching vibration peak of C-O in alcohol moved from 1075cm^-1 to 1073cm^-1,which indicated that there was intermolecular hydrogen bond in PSA.The H-NMR results of PSA further confirmed the existence of hydrogen bonding between the two materials.After plasticizing PVP aqueous solution with plasticizer SYCA,the glass transition temperature of the pressure sensitive adhesive decreased to-67.5℃,and it was in a high elastic state at room temperature,which improved the elasticity of the pressure sensitive adhesive without destroying the viscosity.When the moisture in the PSA was dried,the storage modulus G’increased,the loss factor tanδdecreased,and the cohesive energy strength of the PSA increased significantly.（4）The results show that the initial viscosity test of the new water-soluble tape was 9#steel ball,the holding viscosity test was 1.2mm/h,the 180°peel strength and 90°peel strength were 3.6N/cm and 3.5N/cm respectively,the tensile strength was 88.8 MPa,the tensile breaking stress was 50.8N,the elongation at break was 145.1%,and the maximum puncture strength was 62.4MPa,which could meet the requirements of the national standard for sealing tape.The weight loss rate of the tape reached 78.21%at 80℃,which was water-soluble.In the soil degradation simulation experiment,the final mass loss of the tape was 30.39%.In the composting experiment,the final biodegradation rate of the tape was 63.8%,which met the requirements of the national standard and was degradable.更多还原