while ($row_result_material_name = mysqli_fetch_array($search_material_name)) {

                echo "<tr>";

                    echo "<td class='col-md-'>",$row_result_material_name['idPositionFK'],"</td>";
                    echo "<td>",$row_result_material_name['title'],"</td>";
                    echo "<td>",$row_result_material_name['price']," руб.</td>";
                    echo "<td>",$row_result_material_name['unit'],"</td>";
                    echo "<td>
                               <button id='", $row_result_material_name['idMaterial'] ,"' data-id-material='", $row_result_material_name['idMaterial'] ,"' type='button' class='btn btn-success btn-md btn-wd' data-original-title='' title=''>
                                    <i class='material-icons'>add</i>
                               </button>
                          </td>";
                    echo "

                        <script>

                            $('#",$row_result_material_name['idMaterial'],"').click(function(){

                                var idMaterial_to_add =  $('#",$row_result_material_name['idMaterial'],"').data('id-material');

                                $.ajax({
                                                    url:        'server/express-order/express-add-to-plan.php',
                                                    type:       'POST',
                                                    cache:      false,
                                                    data:       {'idMaterial_to_add':idMaterial_to_add},

                                                    dataType:   'html',

                                                    success: function(data) {


                                                    }
                                });

                        </script>



                    ";


                echo "</tr>";

    }

<button ... class="btn btn-success btn-md btn-wd btn-add-material" ...>
  <i class='material-icons'>add</i>
</button>

$(".btn-add-material").click(function(e) {
  var idMaterial_to_add =  $(this).data('idMaterial');
  ...
});